Footwear / adidas / Ultra Boost / adidas Ultra Boost 21 Cold.Rdy White Signal Green
adidas Ultra Boost 21 Cold.Rdy White Signal Green
S23898 · White Signal Green · 2021
Your size, by email. Free, no account needed.
Some of the links below pay us a commission. Your price never changes. Shops are ordered by price, not by what they pay us.
Where to buy
No shop we check listed this today.
We check again tomorrow at 06:00.

Price, last 90 days
Lowest recorded shop price · EURDetails
About this product
The adidas UltraBoost 21 Cold.Rdy ‘White Signal Green’ showcases fluorescent accents on a performance running shoe made for the cold-weather months. Made in part with 50% recycled materials, the white Primeknit+ upper features no-sew overlays and a molded heel counter with UltraBoost branding in embossed green lettering. The sock-like build is lined in insulated black textile and accented with a neon green pull tab at the heel. A metallic teal hue is applied to the stacked Boost midsole, supported by a Continental WinterGrip Rubber outsole.
Size conversionEU · US · UK · A conversion chart, not stock +−
Scroll within the table to compare sizes.
This table scrolls within its region. Focus this region and use the arrow keys to compare sizes.
| EU | US | UK |
|---|---|---|
| 32 | ||
| 33 | 1.5 | 1 |
| 33 1/2 | 2 | 1.5 |
| 34 | 2.5 | 2 |
| 35 | 3 | 2.5 |
| 35 1/2 | 3.5 | 3 |
| 36 | 4 | 3.5 |
| 36 2/3 | 4.5 | 4 |
| 37 1/3 | 5 | 4.5 |
| 38 | 5.5 | 5 |
| 38 2/3 | 6 | 5.5 |
| 39 1/3 | 6.5 | 6 |
| 40 | 7 | 6.5 |
| 40 2/3 | 7.5 | 7 |
| 41 1/3 | 8 | 7.5 |
| 42 | 8.5 | 8 |
| 42 2/3 | 9 | 8.5 |
| 43 1/3 | 9.5 | 9 |
| 44 | 10 | 9.5 |
| 44 2/3 | 10.5 | 10 |
| 45 1/3 | 11 | 10.5 |
| 46 | 11.5 | 11 |
| 46 2/3 | 12 | 11.5 |
| 47 1/3 | 12.5 | 12 |
| 48 | 13 | 12.5 |
| 48 2/3 | 13.5 | 13 |
| 49 1/3 | 14 | 13.5 |
| 50 | 14.5 | 14 |
| 50 2/3 | 15 | 14.5 |
| 51 1/3 | 16 | 15 |
| 52 2/3 | 17 | 16 |
| 53 1/3 | 18 | 17 |
| 54 2/3 | 19 | 18 |
Reference conversions only; this chart does not measure your foot or describe product fit.
Same shoe, other colours
People also compare

A sneaker shop in Ibiza since 2019. In 2026 we stopped selling and started checking.
Shop prices and available sizes, checked daily. The shelves are empty; the spreadsheet is not. The story






