Fostech - ECHO Sport - Curved - Black - AR-15 Binary TriggerAbout Fostech Fostech is a family owned company based in Southern Indiana. Fostech Inc makes AR 15's, 12 Gauge Shotguns in AR style, binary triggers for both the AR and AK platforms, as well as many AR parts. All Fostech products are proudly made in the United States. The Echo AR II Trigger is a groundbreaking drop in design that is approved by the ATF. The Echo AR II trigger does not come with a bolt carrier. You will need a full auto bolt carrier in