Made to mil-spec standards, allows for adjustment of the buttstock to offer the perfect fit while shooting. Lower Receiver Material: 7075 T6 aluminum with a type 3 hard coat anodizing Hammer/Trigger pin size: Mil-spec small pin .154" Pivot/Takedown Pin Size: Mil-spec small pin - .250" Caliber Marking: Multi Buttstock: Mil-spec 6 position Buffer: Standard carbine buffer and spring Trigger: Mil-spec single stage trigger with a non-adjustable 5-8 pound trigger pull Grip: A2 style plastic grip