Smoke Color. Used 1 time. This is a niche fin that requires all fin boxes to have the 3/4" depth (standard front side fin depth). Roberts Twonzer Fin Sets are solid fiberglass fins designed to work with the special fin placement that Rob designed to provide a blend of twin fin speed with the hold of a quad setup. Choose size Large for riders over 180 lbs or Fish / Grovel / Alt style boards over 5'8 or most Betweener / Performance style boards over 6'2 Please note: Some of our boards, like the Bro Fish, Invader, and Star Chip, are designed with the Twonzer setup in mind but also perform well in other fin configurations. Occasionally, they are ordered by customers or shops in twin, quad, or five-fin setups. To check if a board is Twonzer-compatible, start by looking for the Twonzer logo on the bottom of the board. If the logo isn’t present, you can test compatibility by inserting a front fin from a standard set into the rearward side fin boxes. If the box is deep enough to accommodate the fin, your board is compatible with Twonzer fins.