TANDEMKROSS Accelerator Forward Thumb Ledge for Ruger Mark IV 22/45 Black. With the scalloped texture you get the support you need for steady rapid and accurate shots. With easy non-permanent installation its compatible with both Ruger Mark IV 22/45 factory lowers and TANDEMKROSSs Cthulhu Lower making it a great upgrade for a reliable comfortable grip. Specifications for TANDEMKROSS Accelerator Forward Thumb Ledge for Pistols: Manufacturer: TANDEMKROSS Gun Make: Ruger Gun Model: Ruger Mark IV 22/45 Weight: 0.3 oz Features of TANDEMKROSS Accelerator Forward Thumb Ledge for Pistols Provides stability and control for follow-on shots Encourages proper grip Simple non-permanent installation Package Contents: TANDEMKROSS Accelerator Forward Thumb Ledge for Pistols What firearm models does the manufacturer say TANDEMKROSS Accelerator Forward Thumb Ledge for Pistols is compatible with? The manufacturer suggests that TANDEMKROSS Accelerator Forward Thumb Ledge for Pistols is compatible with Ruger Mark IV 22/45TANDEMKROSS TK26N0535BLK1: Accelerator Forward Thumb Ledge for Ruger Mark IV 22/45 Black