Includes a leaf spring and a trigger ring Spare parts are of great quality and value Compatiable with all Double Bell M1911s Hop up arm make adjustments easier Hammer strut for better air efficiency In the Box 1X Leaf Spring 1X Hammer Strut 1X Trigger Ring 1X Hop Up Arm Specifications: Brand Double Bell Build MetalA Weight 0.5 oz Compatability All Double Bell M1911 Products California Proposition 65 Warning: Cancer and Reproductive Harm - www.P65Warnings.ca.gov