This is the one... - OpticsPlanet Exclusive Franklin Armory BFSIII AR-C1 Trigger - Binary Firing System for AR Platforms

I've tried the other binary units and this one is the one for me. Super-easy to install, nothing ever needs adjustment and it works as it should first time, every time. I've encountered problems with others needing an upgraded spring right out of the box. Needing 3 or more hands to install. Being balky in operation. The exact opposite of this unit. Same install as any other AR trigger, no extra parts and no fear of it flying apart if you don't hold your mouth just right. I can see no need for the others so long as this is around. Less expensive, too!