This is a Kel-Tec Carbine known as the RDB chambered in 556NATO, model RDBDBLK.
Like no ordinary bullpup" the RDB series of rifles redefines the platform. You've never experienced balance or a trigger quite like this in any other design. The RDB is completely ambidextrous due to its patented downward-ejection" magazine catch/release placement" intuitive safety and reversible operating handle. The RDB series of bullpups delivers a 5.56/.223 ballistic advantage in a very compact package that's easy to manipulate for just about anyone.
Features:
Bullpup Design
Adjustable gas piston system
Reversible operating handle