The 661S AR15 Competition Skeletonized Trigger with Small Pin Steel w/ Aluminum Housing Black/Gold. The 661S series showcases a high standard of precision machining and workmanship. Each trigger undergoes individual testing and calibration to ensure quality. This AR-15 compatible single-stage trigger provides a smooth, creep-free pull. The lightweight aluminum housing keeps components secure. The hammer is wire-EDM machined from S7 tool steel and the EDM is formed from A2 tool steel. This model features a small pin and a skeletonized design for maximum performance.