The 3/8″ x 3/8″ Aluminum Two-Piece Clamp – Precision Sleeve Hex Bore Coupling is precision machined from lightweight aluminum and features a solid center section with a smooth square bore for a close-tolerance fit on ground hexagonal shafting. Its Accu-Clamp self-centering design provides high clamping power while maintaining less than 0.001″ TIR concentricity for precise shaft alignment. The fully separable two-piece construction enables easy installation, adjustment, and removal while protecting shafts from marring or damage.