This is a Samson Manufacturing Corp. Rail known as the Evolution, model EVO-9.
The Samson Evolution Series features a free-floating AR-15 rail system. Being lightweight and durable allows the Samson Evolution Series to offer the perfect upgrade for 3-Gun competition shooting" law enforcement and military personnel or weekend enthusiasts. Accessory picatinny rails can be added or removed at any of 7 positions around the rail and any place along the length of the tube. Rail accommodates most piston systems. This is the 9" Carbine Length Evolution Rail for the AR-15.Standard Evolution Series Includes: Thermal bushings" Two (2) 2" accessory rail kits" One (1) 4" accessory rail kit and wrenches.
Features:
Samson Evolution 9 Free-float AR-15 rail system;Rail includes integrated anti-rotation tabs;1913 Picatinny Mil-spec;Forms continuous top rail