Tecnifibre
X-One Biphase Tennis String Natural
X-One Biphase Tennis String Natural
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Tecnifibre X-One Biphase Tennis String Set in Natural is the ultimate synthetic string and provides the closest playability to natural gut of any synthetic string produced. Elastyl Fibers are used, giving 12% more power than the standard polyamide materials used in other synthetic strings. X-One Biphase features a unique technology that separates it from other strings in the Tecnifibre line, Fiber H2C, which involves a high temperature prestretching step to ensure greater tension maintenance. Improving on their PU Inside technology, this string features Trimerized PU, allowing for even more comfort and touch for that natural gut like feel.
Many years of research have led to the Biphase process, a production process that increases string durability by 20%, letting players experience the benefits of this string for even longer. The most advanced synthetic string on the market, X-One Biphase makes the playability of natural gut available in a synthetic alternative. X-One Biphase gives players more power, comfort and feel.
Construction: Multifilament polyamide
Color: Natural
Gauges: 18G / 1.18 mm | 17G / 1.24 mm | 16G / 1.28 mm | 15L / 1.32 mm
Length: 40 ft / 12.2 m
Features:
-Excellent feel for the ball
-Comfortable on the arm and shoulder
-Enhances power
-Great energy return
For more information on strings, see our following blog posts:
Tecnifibre €™s new Polyester String: The Ice Code Cometh
10 Best Multifilament Tennis Strings Today
Need help selecting a string? Check out our Choosing The Right Tennis String guide for more assistance.
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Quick INFO
Shipping Information
Shipping within the United States
We currently offer Standard Shipping to addresses within the United States.
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Shipping Method: USA Standard
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Delivery Time: 3–4 business days (Monday–Friday, excluding holidays)
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Shipping Cost: $20.00 flat rate per order
Order Processing
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Orders are processed within 1–2 business days after payment is received.
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Orders placed after 2:00 PM MST or on weekends will be processed the next business day.
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You will receive a shipping confirmation email with tracking information once your order has shipped.
Shipping Restrictions
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We currently ship to the contiguous United States only.
Delays and Exceptions
While we strive to meet our delivery estimates, please note that shipping times may be affected by weather conditions, carrier delays, or high order volumes during holidays.
Lost or Damaged Packages
If your package arrives damaged or is lost in transit, please contact us within 7 business days of the expected delivery date at info@bellracketstore.com or (719) 100-3312 so we can assist you with a replacement or claim.
Bell Racket Sport is committed to delivering your order safely and promptly. Thank you for shopping with us!
Return & Refund Info
Returns and Exchanges
At Bell Racket Store, your satisfaction is our priority. If you are not completely satisfied with your purchase, you may return or exchange most new, unused items within 30 days of the purchase date for a full refund or store credit.
Conditions for Returns
To qualify for a return or exchange:
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Items must be in new, unused, and resalable condition.
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Items must include original packaging, tags, and proof of purchase (receipt or order confirmation).
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Returns must be initiated within 30 calendar days of the purchase or delivery date.
Non-Returnable Items
The following items cannot be returned or exchanged:
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Gift cards
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Clearance or final sale items
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Customized or special-order products
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Used or damaged merchandise not due to manufacturing defects
Return Process
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In-Store Returns: Bring your item(s) and receipt to our store at
114 North Tejon Street, Colorado Springs, CO 80903. -
Mail Returns: Contact us at info@bellracketstore.com or (719) 100-3312 to obtain a return authorization. Ship the item(s) securely to the address above.
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Customers are responsible for return shipping costs unless the return is due to an error or defective product.
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Refunds
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Refunds will be issued to the original form of payment within 4 business days after the returned item is received and inspected.
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If the product was a gift, store credit may be issued to the recipient.
Exchanges
If you wish to exchange an item for a different size, color, or model, please contact us to arrange the exchange within the 30-day return period.
Defective or Damaged Items
If you receive a defective or damaged item, please contact us immediately at info@bellracketstore.com with your order details and photos of the issue. We will arrange for a replacement or refund at no cost to you.
Bell Racket Store reserves the right to refuse returns that do not meet the conditions above.
Thank you for shopping with us!
Size Guide
Women's Shoe Sizing Chart
| Length of Foot (Inches) | Length of Foot (Centimeters) | US Size | Shoe Size | A | B (Standard) | C |
|---|---|---|---|---|---|---|
| 8 1/2 | 21.6 | 5 | 5 | 2.6" | 2.8" | 3.0" |
| 8 2/3 | 22.0 | 5 1/2 | 5 1/2 | 2.7" | 2.9" | 3.1" |
| 8 5/6 | 22.4 | 6 | 6 | 2.8" | 2.9" | 3.1" |
| 9 | 22.9 | 6 1/2 | 6 1/2 | 2.8" | 3.0" | 3.2" |
| 9 1/16 | 23.3 | 7 | 7 | 2.9" | 3.1" | 3.3" |
| 9 1/3 | 23.7 | 7 1/2 | 7 1/2 | 2.9" | 3.1" | 3.3" |
| 9 1/2 | 24.1 | 8 | 8 | 3.0" | 3.2" | 3.4" |
| 9 2/3 | 24.6 | 8 1/2 | 8.1/2 | 3.1" | 3.3" | 3.4" |
| 9 5/16 | 25 | 9 | 9 | 3.1" | 3.3" | 3.5" |
| 10 | 25.4 | 9 1/2 | 9 1/2 | 3.2" | 3.4" | 3.6" |
| 10 1/6 | 25.8 | 10 | 10 | 3.3" | 3.4" | 3.6" |
| 10 1/3 | 26.2 | 10 1/2 | 10 1/2 | 3.3" | 3.5" | 3.7" |
Men's Shoe Size Chart
| Length of Foot (Inches) | Length of Foot (Centimeters) | US Size | Shoe Size | C | D (Standard) | E |
|---|---|---|---|---|---|---|
| 9 1/3 | 23.7 | 6 | 6 | 3.3" | 3.5" | 3.7" |
| 9 1/2 | 24.1 | 6 1/2 | 6 1/2 | 3.3" | 3.6" | 3.8" |
| 9 2/3 | 24.6 | 7 | 7 | 3.4" | 3.6" | 3.8" |
| 9 4/5 | 25 | 7 1/2 | 7 1/2 | 3.4" | 3.7" | 3.9" |
| 10 | 25.4 | 8 | 8 | 3.5" | 3.8" | 3.9" |
| 10 1/6 | 25.8 | 8 1/2 | 8 1/2 | 3.6" | 3.8"` | 4.0" |
| 10 1/3 | 26.2 | 9 | 9 | 3.6" | 3.9" | 4.1" |
| 10 1/2 | 26.7 | 9 1/2 | 9 1/2 | 3.7" | 3.9" | 4.1" |
| 10 2/3 | 27.1 | 10 | 10 | 3.8" | 4.0" | 4.2" |
| 10 5/6 | 27.5 | 10 1/2 | 10 1/2 | 3.8" | 4.1" | 4.3" |
| 11 | 27.9 | 11 | 11 | 3.9" | 4.1" | 4.3" |
| 11 1/6 | 28.4 | 11 1/2 | 11 1/2 | 3.9" | 4.2" | 4.4" |
| 11 1/3 | 28.8 | 12 | 12 | 4.0" | 4.3" | 4.4" |
| 11 1/2 | 29.2 | 12 1/2 | 12 1/2 | 4.1" | 4.3" | 4.5" |
| 11 2/3 | 29.6 | 13 | 13 | 4.1" | 4.4" | 4.6" |
Men's to Women's Conversion Chart
| Men's | Women's |
|---|---|
| 3.5 | 5 |
| 4 | 5.5 |
| 4.5 | 6 |
| 5 | 6.5 |
| 5.5 | 7 |
| 6 | 7.5 |
| 6.5 | 8 |
| 7 | 8.5 |
| 7.5 | 9 |
| 8 | 9.5 |
| 8.5 | 10 |
| 9 | 10.5 |
| 9.5 | 11 |
| 10 | 11.5 |
International Shoe Size Conversion Charts
Men
| Nike | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 12.5 | 13.0 | 13.5 | 14.0 | 15.0 |
| UK | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 12.5 | 13.0 | 14.0 |
| EUR | 40.0 | 40.5 | 41.0 | 42.0 | 42.5 | 43.0 | 44.0 | 44.5 | 45.0 | 45.5 | 46.0 | 47.0 | 47.5 | 48.0 | 48.5 | 49.5 |
| CM | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 | 27.5 | 28.0 | 28.5 | 29.0 | 29.5 | 30.0 | 30.5 | 31.0 | 31.5 | 32.0 | 33.0 |
| adidas | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 12.5 | 13.0 | 14.0 | 15.0 |
| UK | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 12.5 | 13.5 | 14.5 |
| EUR | 39 1/3 | 40 | 40 2/3 | 41 2/3 | 42 | 42 2/3 | 43 1/3 | 44 | 44 2/3 | 45 1/3 | 46 | 46 2/3 | 47 1/3 | 48 | 49 1/3 | 50 2/3 |
| Asics | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 13.0 | 14.0 |
| EUR | 40.0 | 40.5 | 41.5 | 42.0 | 42.5 | 43.5 | 44.0 | 44.5 | 45.0 | 46.0 | 46.5 | 48.0 | 49.0 |
| CM | -- | 25.5 | 26.0 | 26.5 | 27.0 | 27.5 | 28.0 | -- | 28.5 | 29.0 | 29.5 | 30.5 | 31.0 |
| Fila | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 13.0 | 14.0 |
| UK | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 12.0 | 13.0 |
| EUR | 39.5 | 40.0 | 41.0 | 41.5 | 42.0 | 42.5 | 43.0 | 44.0 | 44.5 | 45.0 | 46.0 | 47.0 | 48.0 |
| CM | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 | 27.5 | 28.0 | 28.5 | 29.0 | 29.5 | 30.0 | 31.0 | 32.0 |
| Head | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 13.0 | 14.0 |
| UK | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 12.0 | 13.0 |
| EUR | 40.0 | 40.5 | 41.0 | 42.0 | 42.5 | 43.0 | 44.0 | 44.5 | 45.0 | 45.5 | 46.0 | 47.5 | 48.5 |
| CM | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 | 27.5 | 28.0 | 28.5 | 29.0 | 29.5 | 30.0 | 31.0 | 32.0 |
| K-Swiss | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 13.0 |
| UK | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 12.0 |
| EUR | 39.0 | 39.5 | 40.0 | 41.0 | 41.5 | 42.0 | 42.5 | 43.0 | 44.0 | 44.5 | 45.0 | 46.0 | 47.0 |
| New Balance | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 12.5 | 13.0 | 14.0 | 15.0 |
| UK | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 12.5 | 13.5 | 14.5 |
| EUR | 40.0 | 40.5 | 41.5 | 42.0 | 42.5 | 43.0 | 44.0 | 44.5 | 45.0 | 45.5 | 46.5 | 47.0 | 47.5 | 49.0 | 50.0 |
| Prince | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 13.0 | 14.0 |
| UK | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 12.0 | 13.0 |
| EUR | 38.0 | 38.5 | 39.0 | 40.0 | 40.5 | 41.0 | 42.0 | 42.5 | 43.0 | 44.0 | 44.5 | 45.0 | 45.5 | 47.0 | 48.0 |
| CM | 24.0 | 24.5 | 25.0 | 25.5 | 26.0 | 26.0 | 27.0 | 27.5 | 28.0 | 28.5 | 29.0 | 29.5 | 30.0 | 31.0 | 32.0 |
| Reebok | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 12.5 | 13.0 | 14.0 | 15.0 |
| UK | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 13.0 | 14.0 |
| EUR | 38.5 | 39.0 | 40.0 | 40.5 | 41.0 | 42.0 | 42.5 | 43.0 | 44.0 | 44.5 | 45.0 | 45.5 | 46.0 | 47.0 | 48.5 | 50.0 |
| CM | 24.5 | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 | 27.5 | 28.0 | 28.5 | 29.0 | 29.5 | 30.0 | 30.5 | 31.0 | 32.0 | 33.0 |
| Wilson | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.0 | 13.0 | 14.0 |
| UK | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 | 11.5 | 12.5 | 13.5 |
| EUR | 39 | 39 2/3 | 40 1/3 | 41 | 41 1/3 | 42 | 42 2/3 | 43 1/3 | 44 | 44 2/3 | 45 1/3 | 46.0 | 46 2/3 | 48 | 49 1/3 |
| CM | 24.0 | 24.5 | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 | 27.5 | 28.0 | 28.5 | 29.0 | 29.5 | 30.0 | 31.0 | 32.0 |
Women
| Nike | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 |
| UK | 3.0 | 3.5 | 4.0 | 4.5 | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 |
| EUR | 36.0 | 36.5 | 37.5 | 38.0 | 38.5 | 39.0 | 40.0 | 40.5 | 41.0 | 42.0 | 42.5 | 43.0 |
| CM | 22.5 | 23.0 | 23.5 | 24.0 | 24.5 | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 | 27.5 | 28.0 |
| adidas | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 |
| UK | 4.5 | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 |
| EUR | 37 1/3 | 38 | 38 2/3 | 39 1/3 | 40 | 40 2/3 | 41 1/3 | 42 | 42 2/3 | 43 1/3 | 44 |
| Asics | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| USA | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 |
| EUR | 37.0 | 37.5 | 38.0 | 39.0 | 39.5 | 40.0 | 40.5 | 41.5 | 42.0 |
| CM | 23.0 | 23.5 | 24.0 | 24.5 | 25.0 | 25.5 | -- | 26.0 | 26.5 |
| Fila | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| USA | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 |
| UK | 3.5 | 4.0 | 4.5 | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 |
| EUR | 36.5 | 37.5 | 38.0 | 38.5 | 39.0 | 39.5 | 40.0 | 41.0 | 42.0 |
| CM | 23.0 | 23.5 | 24.0 | 24.5 | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 |
| Head | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| USA | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 11.0 |
| UK | 3.5 | 4.0 | 4.5 | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.5 |
| EUR | 36.5 | 37.5 | 38.0 | 38.5 | 39.0 | 40.0 | 40.5 | 41.0 | 42.0 | 43.0 |
| CM | 23.0 | 23.5 | 24.0 | 24.5 | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 | 28.0 |
| K-Swiss | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 11.0 |
| UK | 3.0 | 3.5 | 4.0 | 4.5 | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 9.0 |
| EUR | 35.5 | 36.0 | 37.0 | 37.5 | 38.0 | 39.0 | 39.5 | 40.0 | 41.0 | 41.5 | 42.0 | 43.0 |
| New Balance | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 11.0 |
| UK | 3.5 | 4.0 | 4.5 | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 9.0 |
| EUR | 36.0 | 36.5 | 37.0 | 37.5 | 38.0 | 39.0 | 40.0 | 40.5 | 41.0 | 41.5 | 43.0 |
| Prince | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 11.0 |
| UK | 3.0 | 3.5 | 4.0 | 4.5 | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 9.0 |
| EUR | 35.0 | 36.0 | 36.5 | 37.0 | 38.0 | 38.5 | 39.0 | 40.0 | 40.5 | 41.0 | 42.0 | 43.0 |
| CM | 22.0 | 22.5 | 23.0 | 23.5 | 24.0 | 24.5 | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 | 28.0 |
| Reebok | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 |
| UK | 3.5 | 4.0 | 4.5 | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 |
| EUR | 36.0 | 37.0 | 37.5 | 38.0 | 38.5 | 39.0 | 40.0 | 40.5 | 41.0 | 42.0 | 42.5 |
| CM | 23.0 | 23.5 | 24.0 | 24.5 | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 | 27.5 | 28.0 |
| Wilson | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| USA | 5 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | 10.0 | 10.5 | 11.0 |
| UK | 3.0 | 3.5 | 4.0 | 4.5 | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 |
| EUR | 35 2/3 | 36 1/3 | 37 | 37 2/3 | 38 1/3 | 39 | 39 2/3 | 40 1/3 | 41 | 41 1/3 | 42 | 42 2/3 | 43 1/3 |
| CM | 22.0 | 22.5 | 23.0 | 23.5 | 24.0 | 24.5 | 25.0 | 25.5 | 26.0 | 26.5 | 27.0 | 27.5 | 28.0 |
