Itās a bespoke pogie made by Bar Mitts. Did a breakdown of it in this thread: Winter riding in the Midwest - #38 by lidocaineus. Iām holding a puck in that post, but it will accomodate a z.mote with no problem. You may have trouble fitting a GT2B in there .
The other mitten hand (where I donāt need to hold a remote) has a more normal ArcāTeryx Beta Down Mitten. Both are fully windproof and will get and stay extremely warm.
(rando noise to get around the repost guard after I replied to the wrong thread).