This is a Hera USA Grip known as the H15G, model 11.08.01.
Hera USA's AR-15 HFG Pistol Grip is manufactured from impact optimized reinforced polymer. It is both lightweight and durable while providing an internal compartment. Designed to be mounted on Standard Mil-Spec Lower Receivers.
Features:
AR-15 Pistol Grip with storage
Low profile ambidextrous design
A fantastic upgrade for your AR-15 rifle