I train a wide variety of people. Often I have those who struggle with racking the slide regardless of methods used. It can be from arthritis, tissue damage, injuries, loss of limb, age etc.
There are several manufacturers that have combatted this with handguns such as the S&W EZ and a few models like the Ruger SR22.
Sometimes though they want to use a Glock or other handgun that belongs to someone, have been told they’ve gotta have it or whatever. Sometimes they show up to class without a gun or want to try mine. It’s not always my job to talk them out of it. It’s my job to guide them but mostly to train them.
This device helps me do so. Almost everyone can get a finger or a prosthetic in it to rack the slide. It doesn’t interfere with holstering nor most manipulation of the weapon.
The newer design replaces the backplate but I like this as it’s easy on/off for classes.