The TRS Jaws is a voluntary opening gripper where you can set the grip strength by a lever. The grip then varies between very light, maybe under 1 kg or so, to somewhere above 5 kg. This is a first real use report, after I used it permanently since roughly around May 21, 2019, give or take a few hours.
There are just a few points to address at this stage. If you wear a body powered arm for real work [link], you may now buy one.