HIVIZ HRBLW01 Ruger Mark II and Mark III Interchangeable LITEWAVE Front Handgun Sight by Hi-Viz Manufacturer: Hi-Viz Model: Litewave Fits: Ruger MKII, MKIII, Buckmark, Single 6 (with adjustable rear sight only) Does NOT fit: Ruger 22/45 Lite / Browning Challenge, Buckmark 5.5 target, and Buckmark 5.5 field MPN: HRBLW01