Luth-AR Modular Assembly Riffle Trigger 3.5 lb Pull Weight Hardcoat Anodized Aluminum Black. The MTA housing is made from 6061 Hardcoat Anodized Aluminum. The internals are precision cut from EDM process using A2 tool steel and heat treated to 40-45 HRC and utilize SST bushings and springs resulting in a crisp 3 1/2 lb trigger break. Specifications for Luth-AR Modular Assembly Riffle Trigger: Manufacturer: Luth-AR Color: Black Trigger Shape: Curved Trigger Pull Weight: 3.5 lb Trigger Pin Size: 0.154 in Gun Make: AR Platform Gun Model: AR-15 Gun Type: Rifle Finish: Hard Coat Anodized Features of Luth-AR Modular Assembly Riffle Trigger Single Stage Drop-In Trigger Compatible with .22 .223/5.56mm .30 cal Complete Drop-in Assembly Crisp clean trigger break Package Contents: Luth-AR Modular Assembly Riffle Trigger What firearm models does the manufacturer say Luth-AR Modular Assembly Riffle Trigger is compatible with? The manufacturer suggests that Luth-AR Modular Assembly Riffle Trigger is compatible with AR-15Luth-AR LR-MTA: Modular Assembly Riffle Trigger 3.5 lb Pull Weight Hardcoat Anodized Aluminum Black