Forward Controls Design Hammer and Trigger Pins - Pack of 2 Black. Differing from standard TDP pins the HTP features a unique design with a shallow cup/dimple at the tips for secure punch engagement and three grooves to optimally retain the hammer spring. Despite these enhancements the HTP maintains TDP dimensions and tolerances for compatibility with any standard AR-15 or large frame AR-style lower receiver. Specifications for Forward Controls Design Hammer and Trigger Pins - Pack of 2: Manufacturer: Forward Controls Design Color: Black Finish: Heat Treated Fabric/Material: 17-4 Stainless Steel Features of Forward Controls Design Hammer and Trigger Pins - Pack of 2 Adheres to TDP dimensions Features a shallow cup/dimple at the tips Has 3 grooves for hammer spring retention Compatible with standard AR-15 lowers Package Contents: Forward Controls Design Hammer and Trigger Pins - Pack of 2 Forward Controls Design HTP: Hammer and Trigger Pins - Pack of 2 Black