Prototype after prototype. Innovation after innovation. Testing after testing. Meet us in the hot pursuit of the pinnacle harmonization of weight, cushioning, and responsiveness. Ultraboost 21. Say hello to incredible energy return.
Prototype after prototype. Innovation after innovation. Testing after testing. Meet us in the hot pursuit of the pinnacle harmonization of weight, cushioning, and responsiveness. Ultraboost 21. Say hello to incredible energy return.
Prototype after prototype. Innovation after innovation. Testing after testing. Meet us in the hot pursuit of the pinnacle harmonization of weight, cushioning, and responsiveness. Ultraboost 21. Say hello to incredible energy return.
Prototype after prototype. Innovation after innovation. Testing after testing. Meet us in the hot pursuit of the pinnacle harmonization of weight, cushioning, and responsiveness. Ultraboost 21. Say hello to incredible energy return.
Last updated at 03/25/2026 03:06:55
adidas Ultra Boost 21 Grey Sonic Ink
Delivery $34.95
adidas UltraBoost 21 'Grey Sonic Ink' | Men's Size 9
Delivery between 26 Mar – 2 Apr $25
originally posted on stockx.com
Sneakers are well constructed and very comfortable but wish I had a half size down but this is no big surprise with Adidas crazy sizing methods .but guess thankful to be able to cop these period since there's not to many of these in this exact colorway still available
originally posted on roadrunnersports.com
I've been a lifelong Nike endorser until these came out! Amazing shoe! They take a bit to break in but once they do you'll never go back! I was a huge fan of the Nike free runs and was skeptical that these could even come close... but they did! This has been by far my favorite shoe! I used it for track and xc training.
originally posted on Academy Sports + Outdoors
These shoes are pretty decent. They have plenty of cushioning in the heel for heel strikers. I’m enjoying them for my runs.
| Release Date | 08-31-2021 |
| Nickname | Grey Sonic Ink |
| Colorway | Grey Five/Core Black/Screaming Green |
| Upper Material | Primeknit |
| Technology | Boost |
adidas Ultra Boost 21 Grey Sonic Ink
Delivery $34.95
adidas UltraBoost 21 'Grey Sonic Ink' | Men's Size 9
Delivery between 26 Mar – 2 Apr $25
Sneakers are well constructed and very comfortable but wish I had a half size down but this is no big surprise with Adidas crazy sizing methods .but guess thankful to be able to cop these period since there's not to many of these in this exact colorway still available
I've been a lifelong Nike endorser until these came out! Amazing shoe! They take a bit to break in but once they do you'll never go back! I was a huge fan of the Nike free runs and was skeptical that these could even come close... but they did! This has been by far my favorite shoe! I used it for track and xc training.
These shoes are pretty decent. They have plenty of cushioning in the heel for heel strikers. I’m enjoying them for my runs.
I really liked the Ultraboost 20s and bought 2 pairs of the Ultraboost 21 to add in my rotation. I work out 4-5 days a week, doing cardio and weights. And these feel really good on my feet. I am not an avid runner, but as advertised, the additional boost feels more responsive and more cushioned. If you liked the Ultraboost 20s, you'll like the upgrade on the Ultraboost 21s. I am a heavy set guy, I've lost over 60 lbs in the last year, and have put my Ultraboosts through the test...
The fit is almost tight enough not to need any laces. I havent tried the size up. I'm normally a 8.5 on Nike but this is snug fit. The archilles tendon has two plastics to hold the shoe in and its tight if you use any cross training or side movements. Just good for running. Been running on a treadmill and not used outdoor.The top lip of my left shoe flips back and doesnt look all that great when i wear it. If only they moved the adidas label just a bit higher so it wont flip back .
All out red looks exteemely sharp! The extended boost sole looks sharp and provides additional stability. Upper is well made with very little evidence of stich/glue lines. Can wear casually or for running but sole is not flat or firm enough for most gym leg-day exercises. We ordered a full size down as the shoe runs noticably large.
Long distances and wearing these all day every day Man they are great for that......We're going to run in a little heavy but listen I'm not going racing.If you walk man you could take these guys on a 6 mile walk and have your feet and knees be right as rain. The white ones will be impossible to keep clean.
I've had the last three versions of this shoe including an ST version back in the day and this shoe continues to impress. I do a lot of hill work and the new toe plate has been great working through my transitions. I'm normally a size 13 but I always size up for the extra toe box room and this one continued with that trend. The toe plate makes the shoe a tad firmer on the ball of the foot but the performance is still there and it's my new daily work horse. I'm 6'1" and 220lb and this shoe definitely gets the job done.
Oh my gosh this shoe is insanely comfortable. Put them on for the first time yesterday and I haven’t felt like taking them off. I’ve been a huge fan of the boost material for a couple years and I will have to say these are the most comfortable pair I have had.
Fits TTS. I liked the feel of the new boost but I couldn’t get over the chunkiness of the heel. Felt a bit heavier than the older boosts too. If you like the chunky style it’s a definite buy!
| Release Date | 08-31-2021 |
| Nickname | Grey Sonic Ink |
| Colorway | Grey Five/Core Black/Screaming Green |
| Upper Material | Primeknit |
| Technology | Boost |