Blackout Defense AR-15 Bolt Catch FDE. It improves access to the factory bolt catch s lower paddle which can be difficult to reach with an ambidextrous mag release. Specifications for Blackout Defense AR-15 Bolt Catch: Manufacturer: Blackout Defense Gun Model: AR-15 Finish: Anodized Package Contents: Blackout Defense AR-15 Bolt Catch What firearm models does the manufacturer say Blackout Defense AR-15 Bolt Catch is compatible with? The manufacturer says that Blackout Defense AR-15 Bolt Catch is compatible with AR-15Blackout Defense BOLTCATCH-FDE: AR-15 Bolt Catch FDE