This device can be operated with little to no grip strength.
For people with missing digits and/or reduced digital dexterity this device can be operated with a minimum of one finger and can accommodate a maximum of three fingers in the device but you can obviously use you whole hand if you want.
The device can fit comfortably in a pocket and with the fluorescent color it lends itself to easy identification even in low light settings.
In addition to the 3-d print, I use one 4mm bolt, two 4mm nuts and one 4mm washer to secure a wide variety of keys within the recessed area of the device. Behind the handle of the key is a short slot which allows for keys with varying handle sizes and handle hole locations. With a small modification a key loop can be added so that it can be attached to a traditional lanyard or keychain.