• Gen. 2 version does not include carrier
• Works with any Mil-Spec BCG's w/ the M-16 (full auto) cut 
• Also works with pistol caliber carbines with M-16 cut and wide raceway (some PCC bolts require machining)
• For direct impingement AR-15's
• Safe, semi, and Echo modes
• Echo mode means a shot is fired upon pull and release
• Second shot won't fire on Echo mode if safe or semi modes are selected
• Carrier override or hammer follow won't happen
• Very safe design
• Design gained ATF approval (Patent # US 8,820,211 B1)
• Will not currently ship to North Dakota, Oregon, Washington, or New Jersey
• No returns on this item, per Fostech

The Fostech Echo Gen2 Trigger is designed using truly cutting edge technology that has not been previously available. This trigger, unlike other designs, will only mechanically let you shoot at a fixed speed. The Echo's design feature fixes the problem of hammer follow or carrier override, so you won't have to cycle your action. This means that the hammer won't drop prematurely with a live round chambered. If you are in Echo mode and have depressed the trigger but don't want to fire another shot, just move the selector to safe or semi auto and your gun will not fire. Since certain states have defined the term of machine-gun to be more stringent than Federal definitions, we currently can not ship this trigger to the listed states above. However if you do not live in these states this new age design is something that can be used for a wide variety of tasks. 

For more info, visit Fostech