Birkenstock Birko Flex Arch Support Insoles
Overview
For those looking for pure foot support without any additional features, the Birkenstock Birko Flex Insoles should be your go-to choice. These insoles are made from pure unlined solid EVA, offering a rigid support shell without any padding, cushioning, or top-cover. Reminiscent of custom orthotics, these insoles will provide... read more
Birkenstock Birko Flex Arch Support Insoles - #35: Women's 4 / Medium is backordered and will ship as soon as it is back in stock.
Men's Size Conversions
| U.S. SIZE | EURO SIZE | UK SIZE | INCHES | CM |
| 6 | 39 | 5.5 | 9 1/3" | 23 3/4 cm |
| 6.5 | 39 | 6 | 9 1/2" | 24 1/10 cm |
| 7 | 40 | 6.5 | 9 2/3" | 24 1/2 cm |
| 7.5 | 40-41 | 7 | 9 5/6" | 25 cm |
| 8 | 41 | 7.5 | 10" | 25 2/5 cm |
| 8.5 | 41-42 | 8 | 10 1/6" | 25 4/5 cm |
| 9 | 42 | 8.5 | 10 1/3" | 26 1/4 cm |
| 9.5 | 42-43 | 9 | 10 1/2" | 26 7/10 cm |
| 10 | 43 | 9.5 | 10 2/3" | 27 cm |
| 10.5 | 43-44 | 10 | 10 5/6" | 27 1/2 cm |
| 11 | 44 | 10.5 | 11" | 28 cm |
| 11.5 | 44-45 | 11 | 11 1/6" | 28 2/5 cm |
| 12 | 45 | 11.5 | 11 1/3" | 28 4/5 cm |
| 13 | 46 | 12.5 | 11 1/2" | 29 1/5 cm |
| 14 | 47 | 13.5 | 11 2/3" | 29 3/5 cm |
| 15 | 48 | 14.5 | 11 5/6" | 30 cm |
| 16 | 49 | 15.5 | 12" | 30 1/2 cm |
Women's Size Conversions
| U.S. SIZE | EURO SIZE | UK SIZE | INCHES | CM |
| 4 | 35 | 2 | 8 1/3" | 20 1/5 cm |
| 4.5 | 35-36 | 2.5 | 8 1/2" | 21 3/5 cm |
| 5 | 36 | 3 | 8 2/3" | 22 cm |
| 5.5 | 36-37 | 3.5 | 8 3/4" | 22 1/4 cm |
| 6 | 37 | 4 | 9" | 22 4/5 cm |
| 6.5 | 37-38 | 4.5 | 9 1/6" | 23 cm |
| 7 | 38 | 5 | 9 1/3" | 23 3/4 cm |
| 7.5 | 38-39 | 5.5 | 9 1/2" | 24 1/10 cm |
| 8 | 39 | 6 | 9 2/3" | 24 1/2 cm |
| 8.5 | 39-40 | 6.5 | 9 5/6" | 25 cm |
| 9 | 40 | 7 | 10" | 25 2/5 cm |
| 9.5 | 40-41 | 7.5 | 10 1/6" | 26 cm |
| 10 | 41 | 8 | 10 1/3" | 26 4/5 cm |
| 10.5 | 41-42 | 9 | 10 1/2" | 26 3/5 cm |
| 11 | 42 | 9.5 | 10 2/3" | 27 1/10 cm |
| 11.5 | 42-43 | 10 | 10 5/6" | 27 1/2 cm |
| 12 | 43 | 10.5 | 11" | 28 cm |
Children's & Youth Size Conversions
Children's Size Conversions
| U.S. SIZE | EURO SIZE | UK SIZE | INCHES | CM |
| 5.5 | 21 | 4.5 | 5 1/6" | 13 1/10 cm |
| 6 | 22 | 5 | 5 1/4" | 13 1/3 cm |
| 6.5 | 22 | 5.5 | 5 5/12" | 13 3/4 cm |
| 7 | 23 | 6 | 5 7/12" | 14 1/5 cm |
| 7.5 | 23 | 6.5 | 5 3/4" | 14 3/5 cm |
| 8 | 24 | 7 | 5 11/12" | 15 cm |
| 8.5 | 25 | 7.5 | 6 1/12" | 15 1/2 cm |
| 9 | 25 | 8 | 6 1/4" | 15 4/5 cm |
| 9.5 | 26 | 8.5 | 6 5/12" | 6 1/3 cm |
| 10 | 27 | 9 | 6 7/12" | 16 3/4 cm |
| 10.5 | 27 | 9.5 | 6 3/4" | 17 1/5 cm |
| 11 | 28 | 10 | 6 11/12" | 17 3/5 cm |
| 11.5 | 29 | 10.5 | 7 1/12" | 18 cm |
Youth Size Conversions
| U.S. SIZE | EURO SIZE | UK SIZE | INCHES | CM |
| 12.5 | 30 | 11.5 | 7 5/12" | 18 4/5 cm |
| 13 | 31 | 12 | 7 7/12" | 19. 1/4 cm |
| 13.5 | 31 | 12.5 | 7 3/4" | 19 3/5 cm |
| 1 | 32 | 13 | 7 1/3" | 18 3/5 cm |
| 1.5 | 33 | 14 | 7 1/2" | 19 cm |
| 2 | 33 | 1 | 7 2/3" | 19.5 cm |
| 2.5 | 34 | 1.5 | 7 5/6" | 20 cm |
| 3 | 34 | 2 | 8" | 20 1/3 cm |
| 3.5 | 35 | 2.5 | 8 1/6" | 21 3/4 cm |
| 4 | 36 | 3 | 8 1/3" | 21 1/5 cm |
| 4.5 | 36 | 3.5 | 8 1/2" | 21 3/5cm |
| 5 | 37 | 4 | 8 2/3" | 22 cm |
| 5.5 | 37 | 4.5 | 8 5/6" | 22 2/5 cm |
| 6 | 38 | 5 | 9" | 22 4/5 cm |
| 6.5 | 38 | 5.5 | 9 1/6" | 23 1/3 cm |
| 7 | 39 | 6 | 9 1/3" | 23 7/10 cm |
Please Note: Most manufacturers have their own specific sizing. If you have any questions, please feel free to contact our Customer Service Team.
Birkenstock Birko Flex Arch Support Insoles - #35: Women's 4 / Medium is backordered and will ship as soon as it is back in stock.
About the Birkenstock Birko Flex Arch Support Insoles
Overview
For those looking for pure foot support without any additional features, the Birkenstock Birko Flex Insoles should be your go-to choice. These insoles are made from pure unlined solid EVA, offering a rigid support shell without any padding, cushioning, or top-cover. Reminiscent of custom orthotics, these insoles will provide firm support for the heel, arch, and metatarsals in a design that is extremely low-profile, waterproof, and lightweight.
Description
These insoles are made of rigid, anatomically-shaped solid EVA that offer a firm, neutral-height arch support, heel cradle, metatarsal support, and raised side flanges to help control both over-pronation and supination. Designed purely to provide support, these insoles have no top-cover, cushioning, or other such features. However, the anatomical shape will provide natural cushioning and pressure relief by properly supporting the foot and more effectively distributing pressure and impact shock.
Notes
- Available in medium and wide widths.
- Waterproof.
- Made in Germany.
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Product CategoryArch Support Insoles, 3/4-Length Insoles
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Trim-to-Fit-
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Arch Support TypeSemi-Rigid
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Arch Height
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Forefoot Thickness-
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Cushioning Density
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Metatarsal Pad
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Ball-of-Foot Strike Pad
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Heel Strike Pad
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MaterialsPlastic
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Model/Style
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Wear-Test Guarantee
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APMA Accepted-
Foot Conditions & Pain Relief
Athletics & Activities
Work & Lifestyle
Shoe Types
Foot Arch Heights
Use
For more information on using your new insole, visit our Help Center to see common usage FAQs.
Care
For more information on caring for your insoles, visit our Help Center to see common product care FAQs.
Warranty
For additional information on wear-test guarantees, see our Returns Policy.
Returns
All products — except for gift cards, clearance items, and closeout items — may be returned within 60 days of delivery so long as the product is in brand-new, unworn, unused condition and is returned in the original product condition along with all of the original product packaging and labels.
Products with wear-test guarantees can be returned even if used/worn. See our Returns Policy for more information.



