This is a Mossberg Grip known as the Grip, model 95218.
This Mossberg FLEX System Shotgun Pistol Grip is made of polymer and features grooves for increased grip. Built on the Mossberg 500/590 platform" FLEX shotguns share the same durability and proven engineering with the convenience of their Tool-less Locking System. The TLS system is a series of three connectors that allows shooters to easily switch stocks" forends and recoil pads for different shooting applications. Fits Mossberg FLEX 500 and 590 shotguns only.
Features:
FLEX system shotgun pistol grip
Fits Mossberg FLEX 500 and 590 shotguns only