Mars Trigger Knuckle Duster AR Grip Black. Ergonomic design reduces hand fatigue and provides superior grip stability. Specifications for Mars Trigger Knuckle Duster AR Grip: Manufacturer: Mars Trigger Color: Black Gun Model: AR-15 Features of Mars Trigger Knuckle Duster AR Grip Aggressive texturing Ergonomic palm swell Enhanced finger grooves Impact-resistant construction High-strength polymer Package Contents: Mars Trigger Knuckle Duster AR Grip What firearm models does the manufacturer say Mars Trigger Knuckle Duster AR Grip is compatible with? The manufacturer says that Mars Trigger Knuckle Duster AR Grip is compatible with AR-15Mars Trigger A026-CMP-002-V01: Knuckle Duster AR Grip Black