Semien wears the W-107 sliding mitt from Benik in all blue. This mitt is very similar to the W-117B, but it does not cover the thumb at all and focuses all of its protection on the wrist. There are other sliders out there that do a better job of completely covering your whole hand, but if you only want wrist support, the W-107 is a great option.
You won’t be able to order it directly from Take a look at this webpage for ordering information. You can also check out the CFX PRT sliding mitt from Franklin which provides similar protection but also covers the fingers/thumb. Get it at DicksSportingGoods.com for $50., but you can call 1-800-442-8910 to get your own.