Tiger Rock AR-15 Pistol Buffer Tube Locking Collar Black. It stops any forward sliding of a Pistol Stabilizing Brace e.g. Sig Saur SBX Brace. Specifications for Tiger Rock AR-15 Pistol Buffer Tube Locking Collar: Manufacturer: Tiger Rock Gun Type: Rifle Gun Model: AR-15 Fabric/Material: 6061-T6 Aluminum Quantity: 1 Features of Tiger Rock AR-15 Pistol Buffer Tube Locking Collar: Fits 1.125" to 1.1875 diameter tubes Package Contents: Tiger Rock AR-15 Pistol Buffer Tube Locking Collar Hex Screw What firearm models does the manufacturer say Tiger Rock AR-15 Pistol Buffer Tube Locking Collar is compatible with? The manufacturer says that Tiger Rock AR-15 Pistol Buffer Tube Locking Collar is compatible with AR-15Tiger Rock LCR: AR-15 Pistol Buffer Tube Locking Collar Black