I ordered a bike adapter termed "Freelock" from Stel Orthopedie in the Netherlands.
The device is a socket-mount only piece; there are no required handle bar mounts (as the Mert hand essentially is a two-piece adapter).
The Freelock metal adapter goes on the arm, obviously. But it ships with a hard plastic grip to put on the bike handle bar, that appears to be specially crafted, but due to that hard plastic grip's smooth and hard surface I figured better to use normal soft rubber handle bar covers - better angulation, softer shocks, better dampening, easier overall also with shifting use across several bikes. The Mert hand is great as it works so well, but it is a bitch to always reposition the handle bar side part of the quick release adapter.
The Freelock also has a quick release mechanism. The "thumb" pulls out and the spring (black plastic button to turn screw) can be set from anywhere between totally light weight to insanely tight.