I use the voluntary closing (VC) Grip 5 Evolution Prehensor by TRS on my body powered prosthetic arm - the terminal device that Bob Radocy used when winning both heat and final of the Cybathlon prosthetic arm race - for a first bike ride. No modifications of bicycle, handlebar or prosthetic arm necessary whatsoever.
I wear it to ride my Gerber race bike, the first animated image also shows the fluency of the handle bar grab with the socket mounted camera:
It stands out against the bike handlebar specific adapters Freelock and Mert hand:
- it closes very comfortably but also extremely firmly (with up to 25 kg closing force easily)
- it closes as long as I make my back round, lean back or extend the elbow, or all / any of these
- but it lets go as soon as I change position so it seems to be far safer than any of these bike specific adapters
- it remains as useful off the bike - so to go eating out, going for a drink, or using a tool, drinking bottle or whatnot while on the way, is easy (not like with the specific bike adapters)
Have not tried it for longer distances or difficult rides yet.