levels.svg levels icon sort-down.svg sort down icon sort-up.svg sort up icon search.svg search icon user-circle.svg user circle icon cart-alt.svg cart icon plus.svg plus icon chevron-left.svg chevron left icon chevron-right.svg chevron right icon phone.svg phone icon zoom-in.svg zoom in icon
Swipe for More


Everything To Know About Binary Triggers
Everything To Know About Binary Triggers
25:36 | 1 year ago

Fostech Echo Sport Trigger Fast Fire Trigger System - 4140

MPN: 4140  |  UPC: 639266300502
sale price $249 99 $299.99

In Stock


The Echo Sport Trigger from Fostech provides the same pull-and-release firing functionality of the original Fostech Echo AR-II Trigger, but the controls have been modified to eliminate the use of the 3rd safety selector position. Instead, a control paddle in front of the trigger guard moves side to side to select single fire or Echo firing modes. Same functionality, but at a significantly lower price!

The Echo Sport Trigger allows the shooter to select from 3 different settings:

Safe Mode: Firearm will not fire. 
Semi-Automatic Mode: Firearm fires when the trigger is pulled. 
Echo Mode: Firearm fires when the trigger is pulled and also when the trigger is released. 

The Echo Sport is different from Fostech’s Echo AR-II in that there’s an added paddle switch in front of the trigger to change firing modes from binary to standard semi-automatic firing instead of using the safety selector like the original Echo trigger.

When the shooter is in the Echo Mode and depresses the trigger firing one round, the shooter can move the paddle to the semi position while firmly holding the trigger rearward and a second round will not fire upon release. 

Patent Pending new ATF Approved design. Not a single drop-in assembly like the original, the Sport functions with any full-auto style bolt carrier.

This item cannot ship to California, the District of Columbia, Iowa, New Jersey, New York, Hawaii, Rhode Island, Flordia, Maryland, Connecticut, Washington, Oregon, Massachusetts.



The Echo Trigger has several distinct features:

  • Patent-pending ATF Approved new design 
  • Light, clean, and crisp pull in Semi-Automatic Mode
  • Trigger Shape - Traditional Curved
  • Trigger Pull Weight - Range 5-8 lb
  • New paddle control design, eliminates use of 3rd selector position
  • Reliable function in Echo Mode
Country of Manufacture United States
License Requirement None
Manufacturer Fostech
Mfg. Part Number 4140
UPC 639266300502
Caliber/Gauge No
Action No
Barrel Length No
Barrel Twist No
Barrel Bore Type No
Barrel Finish No
Barrel Fluting No
Barrel Profile No
Mount Type No
Beam Color No
Firearm Fit AR-15
Threaded Barrel No
Condition New
Free Shipping No

Why Customers Bought This

Questions & Answers

Customer Photos & Videos