This is a Caldwell Bipod known as the Prone, model 534455.
Caldwell's AR Bipod Prone 7.5"-10" combines a quick attach system for securing to any picatinny rail. Its built in systems for both pivot and cant movements give the shooter maximum range of alignment without having to reposition the bipod. The unique internal spring system is both low profile and quiet. The unique leg adjustment mechanism delivers fast and secure" no-wobble height positioning. Rubber feet ensure good grip on all surfaces. Lightweight and durable anodized aluminum construction.
Features:
Quickly attaches/detaches to any picatinny rail
20 degree pan left and right capable
18 degree cant right and left capable