The FosTech Echo AR-II Trigger (brand part no. 4150) is a drop-in trigger for AR-15 platform rifles, built by FosTech Outdoors around its patented Echo Mode fire control system. In standard mode, the Echo AR-II functions like any quality single-stage AR trigger, but switching to Echo Mode lets the trigger fire one round on the pull and a second round on the release, giving experienced shooters faster split times between shots. The trigger is made in the USA and installs as a direct drop-in replacement for a factory AR-15 fire control group, with no permanent modification to the receiver required. It’s built for AR-15 owners who want the option to switch between a standard semi-automatic trigger pull and FosTech’s faster Echo Mode depending on the situation.

Key Specifications

• Installs as a drop-in trigger for standard AR-15 platform rifles.
• Requires no permanent receiver modification to install.
• Offers a selectable Echo Mode, firing one round on the trigger pull and a second on the release.
• Functions as a standard single-stage trigger when Echo Mode is not engaged.
• Manufactured in the USA by FosTech Outdoors.

Frequently Asked Questions

How does Echo Mode work? Echo Mode fires one round when the trigger is pulled and a second round when the trigger is released, letting an experienced shooter close split times between shots.

Do I have to run it in Echo Mode? No, the trigger switches between a standard single-stage pull and Echo Mode, so it functions as a normal AR-15 trigger whenever Echo Mode isn’t selected.

Will this work in every state? Binary-style triggers like the Echo AR-II are restricted or prohibited in some states, so buyers should confirm their local and state laws before purchasing.

Buy the FosTech Echo AR-II Drop-In Binary Trigger for AR-15

Add FosTech’s selectable Echo Mode to your AR-15 build. Order it through our FosTech Outdoors lineup of gun accessories and parts from our Lubbock, Texas gun shop.