FosTech Echo AR-II Drop In Trigger

Features

1. Three-Position Selector — Switch between Safe, Semi-Automatic, and Echo (binary) modes directly from the safety selector for instant fire control changes.
2. Binary Echo Mode — Fires one round on trigger pull and a second round on trigger release, dramatically increasing rate of fire while remaining fully semi-automatic.
3. True Drop-In Installation — Self-contained housing drops straight into any mil-spec AR-15 lower receiver with standard trigger pins — no gunsmithing required.
4. No Proprietary Bolt Carrier Required — Gen II design works with any standard full-auto profile AR-15 bolt carrier group, eliminating the need for FosTech's previously required proprietary BCG.
5. Crisp Semi-Auto Pull — Delivers a clean 4.5–5 lb pull weight in semi-automatic mode for precise, controllable single shots.
6. Patented ATF-Approved Design — Engineered under U.S. Patent #8,820,211 B1 and approved by the BATFE for civilian ownership in states where binary triggers are legal.
7. Hardened Steel Internals — Precision-machined fire control components built to withstand high round counts and the increased cycling rate of binary fire.
8. Traditional Curved Trigger Shoe — Familiar curved profile gives a natural finger placement that shooters trained on standard AR triggers will recognize immediately.
9. AR-15 Platform Compatible — Designed to fit the vast majority of mil-spec AR-15 lowers chambered in 5.56 NATO, .223 Rem, and other standard AR cartridges.