Volquartsen Firearms Extended Pistol Bolt Release Ruger MK IV 22/45 Black. Our extended bolt release gives you more surface area and deep serrations for easy thumb engagement. The bolt release pad is CNC machined from 416 stainless and extends .050" further than the factory release. This .050" extension combined with the improved ergonomic flat design of this release is an improvement that every target shooter is looking for. Specifications for Volquartsen Firearms Extended Pistol Bolt Release Ruger MK IV 22/45: Manufacturer: Volquartsen Firearms Color: Black Gun Make: Ruger Gun Type: Pistol Gun Model: Ruger Mark IV 22/45 Fabric/Material: 416 Stainless Steel Condition: New Country of Origin: USA Package Contents: Volquartsen Firearms Extended Pistol Bolt Release Ruger MK IV 22/45 What firearm models does the manufacturer say Volquartsen Firearms Extended Pistol Bolt Release Ruger MK IV 22/45 is compatible with? The manufacturer says that Volquartsen Firearms Extended Pistol Bolt Release Ruger MK IV 22/45 is compatible with Ruger Mark IV 22/45Volquartsen Firearms VC4SR-45-B: Extended Pistol Bolt Release Ruger MK IV 22/45 Black