This is a Geissele Automatics Trigger, model 05-181.
Hi-Speed National Match Triggers Geissele Automatics currently offers three large pin Hi-Speed trigger products. These adjustable triggers are specially designed for competition" hunting" tactical" and military use" where both accuracy and robustness are critical. As an adjustable trigger" the first and second stage weight distribution" as well as" total pull weight" over-travel" and sear engagement are all to be tuned to the shooters preference.
Features:
SERVICE RIFLE: TYPE: 2 Stage 1st Stage Weight: 3.2-5lbs.2nd Stage Weight: 0.5-1.5lbs.Total Pull Weight: As low as 4.5lbs.