DoubleStar is a high quality manufacturer of AR-15 parts and accessories. This particular part is a receiver extension/buffer tub for an AR-15 pistol build. It includes the carbine length spring and buffer, and features a 1.25" ambidextrous sling mount.

Specifications and Features:
7075-T6 Aluminum
Overall Length: 7.25:
1.25" Ambidextrous sling mount
Billet Machined Gusset
Foam OverTube (cut to length)
Carbine buffer and spring included

Fits:

AR-15 lower receivers