EDSON CORPORATION Stainless Power Knob Silver The Mounting Clamp is Designed for an Oval Ring Bar. If Your Wheel is Round Stock, You Could Reshaped the Lower Piece Slightly with Two Pairs of Pliers. The Mounting Clamp is NOT Round. Made of all machined and polished stainless steel. It's not hollow. it is a monolithic block of stainless steel. Can hold up to aggressive wheel manipulation, salt/brackish/fresh water. It fits the oblong cross section of a "Destroyer wheel" perfectly. It is made to fasten over on a wheel spoke which gives an unequivocal positive control of the wheel. It allows you total. It comes with a lock-nut, the kind of metal nut with threads and insert crimped in to keep it from backing out on its own. When it's tightened up securely it's not going anywhere. The compact size keeps it from being an issue on large center console. It easily clears the throttle quadrant with enough room to spare that there's no chance of it hanging up on the. MODEL NO - 969ST-18