This design is based on the Pachmayr Slide Rack Assist and functions in the same way.

This is a slide rack assist for a handgun. Shooters with small hands, those with arthritis, and others with limited hand strength often struggle working the slide on many pistols. This device fits over the slide and muzzle of your handgun, and provides a greatly increased gripping surface and significantly reduces the effort needed to rack a slide. This design is scaled to fit a compact 9mm, specifically a Ruger EC9s. So you may need to adjust the size to fit your own gun.