The Stonfo Hackle Gauge is an essential bench‑tool for fly tyers who demand speed and accuracy when selecting hackle and hook sizes. Simply bend your feather around the plastic pin, then read the matching hook size on the curved scale. The graphic overlay clearly shows hook sizes from #22 to #4, and the coloured curved scale ensures instant readability even when handling light or dark hackles. Mount it directly on your vise stem and rotate it out of the way when not in use—no extra bench clutter.