20mm X 20mm Metric Rigid Shaft Coupling One-Piece Split Clamp-Type, SSFully metric, including clamp screws Mate two shafts with zero backlash Keyways provide added torque capacity and fixed shaft phasing Smooth bore protects shafts from damage Superior torque capacity over set screw type couplings Stafford Metric Rigid Shaft Couplings are fully metric in all specifications, including the clamping screws. Designed for aligned shafts, the 1 Piece Clamp Type Coupling makes two shafts function as one. Standard keyways