The HMH Standard, Spartan, CX CrossOver and ST Vises all have our famous interchangeable jaw option - making these vises the most versatile of fly tying vises on the market. Features: Through-hardended chrome-moly tool steel Best access to any hook Change jaws without tools in seconds 40+ years of proven dependability Guaranteed for Life Omni Jaw for hook sizes 20 to 2/0 Micro Jaw for hook sizes 32 to 18 Magnum Jaw for hook sizes 10 to 6/0+