The TMC Twin Hackle Gauge:
To set the gauge, just slide down the stem of the fly tying vise through the hole. In order to tie beautiful flies, the TMC Twin Hackle Gauge has two pins; one is for standard patterns, the other one is for parachute patterns. Experts know that they need two different sizes of hackle. (Standard Hook: our popular fly hook/TMC100). The hackle will not slip around the tapered pins while measuring. The hole is a little bigger than the diameter of vise stem so that the gauge will have an angle towards tyers and rotate easily while not in use. Fits onto most vise stems.