The Gapper fills the gap between the trigger guard and the pistol grip on the AR-15/M-16 and cushions your knuckle, prevents abrasions to your finger and provides a more finished look.  The Gapper is made from a solvent resistant rubber, clips in easily, friction fit holds it in place.

Simple Installation Instructions for the Ergo Gapper™

Slide the "U" shaped portion of the Gapper™ over the rear of the trigger guard with the longer side pointing down and push it forward. If it can not be pressed in easily, try moistening it, or as a last resort loosen the grip by untightening the grip mounting screw. After the Gapper™ is positioned all the way forward retighten the mounting screw.