Brand: Presma Includes: Stabilizing Fin, Allen Key and screws Materials: Injection Molded Polymer Compatibility: AR Pistols Weight: 10 oz Color: Black Warranty: Lifetime Does not fit adjustable tubes (Mil-Spec/Commercial) or A2 rifle tubes. This Stabilizing Fin incorporates a flexible stabilizing area which rests against the inside of the forearm when in the firing position. If desired, a standard sling may be wrapped around the Fin and forearm, further stabilizing the pistol to the forearm in both horizontal and vertical planes.