The Fox Butt Lok is a sturdy support that keeps the rear of the rod in place. The hard plastic frame features a soft yet wear-resistant rubber outer layer that grips firmly around the handle. Small, Medium and Large offer different openings for varying handle thicknesses. The Duo version is designed for anglers who switch between full cork or duplon handles and thinner abbreviated or shrink wrap handles. A rubber O-ring is included to align the rest neatly on the buzzer bar.