The TRS Adult Grip Prehensor is a bit like an American car. You may want to tune it, even try to tune it well, before you cant take it out to really shine. Not literally "shine", though. Proverbially! Really I do not need this here to actually shine. It is totally OK if it just makes me look less bad, like, by supporting me, grip wise.
My prehensor is light and extremely sturdy. The bare model provides tons of mechanic functionality. However, grip aspects are left to the user - and I mean self understood, archaic, historically true grip aspects that were always there [link] and that I already had addressed earlier, possibly not just as sophisticated [link] also for the V2P prehensor [link].
So I first put double sided sticky tape into place. It is a light adhesive (really it does not provide super glue strength but once you want to replace it later, and take the old stuff off, you may understand why that is a loot cooler than it seems now).
I cut sheet rubber (here: red) to size and place it onto the double sided white sticky tape. Where the rubber and sticky tape risk to coil off due to stiffness, I fix it to the prehensor with (also only very mildly adhesive) isolation tape (blue). Also that comes of very easily later while it also allows for stretch and adaptation for curved shapes.
Both red rubber parts are in place now.
Oh and I recently found these cheap rubber finger tips. Original package photo see below/ I add these for added coolness, and, added grip performance.
These are the finger tips that I had bought (buy wherever, such as here [link].
Over these, I pull two fingers of whatever type of working gloves I got lying around, that have latex or nitrile covers.
What I end up with is a voluntary closing device whose surface geometry allows for insane grip performance already at the lowest of body power employed. As with shoe soles, the softer the grip surfaces, the better the grip, but the faster they wear down. It is the same with prosthetic gripper materials. Given that I want insane grip and that I want to swap them weekly, convenience and cost are the next factors.
Seeing how the above setup is made, one can safely leave the deeper layers all in place as long as they are intact, not contaminated and otherwise functional. In fact, I usually pull two glove fingers over each claw and just swap the outermost one after a week or so.
A good gripper allows to easily use conveniently available products for this. I got myself a large sheet rubber roll from some flooring department a while back, so most of my sheet rubber replacements will look red for the next few years or so.
Double sided sticky tape can be bought in most hardware stores, as well as working gloves. If you want softer finger tips, you may as well just fold some cut out sponge material, or - if it has to be slightly stiffer - folded PVC, leather or rubber from anywhere else.
Performance videos here [link].