40mm Metric Shaft Collar One-Piece Split Clamp-Type, SteelFully metric, including clamp screw Smooth bore protects shafts from damage Superior holding power over set screw type collars Stafford Metric Shaft Collars are fully metric in all specifications, including the clamping screws. 1 Piece Clamp Type Shaft Collars are designed for use on standard round shafts, hard or soft, as well as on thin wall tube or over a split hub. They are precision machined, non marring, easy to adjust, with high clamping power.