The HMH Standard, Spartan, CX Cross-Over and ST VISES all have our famous interchangeable jaw option making these vises the most versatile of fly tying vises on the market. The Micro Jaw is designed for small hooks in sizes 32 to 18. Simply remove the existing jaw from the vise and replace it with the Micro Jaw. It’s that simple. Lifetime Guarantee. Made in the USA.