Versa-PodŽ 150-616: Foregrip Adapter, Extended Length Version Versa-Pod® 150-616: Foregrip Adapter, Extended Length Version
Specification:

The Model 616 is an extremely strong design with an all steel chassis, and with Nylon 44 molding it is very comfortable as well. It fits any MIL-STD-1913 Picatinny Rail with a total length of 5 ¼". Full Axial Rotation. Weight: 0.86 lb (0.39 kg)