This is a Ergo Grip , model 4085.
Fills the gap between the trigger guard and the pistol grip on the AR/M4 and cushions your knuckle. Prevents abrasion to you finger and provides a more finished look to your rifle. The GAPPER is chemical resistant" clips in easily" and secures with a tight friction fit.
Features:
Chemical resistant
Increases grip comfort
Fills the gap between the trigger guard and the pistol grip
