Provides torque transmision and alignment Cost effective coupling design Easily installed where major disassembly would otherwise be required Tolerance: +.0005/+.0030 Black oxide provides some corrosion resistance Summit Collars & Industrial Supply Set Screw Couplings are the most cost effective Rigid Coupling design. If additional torque capacity is required, we also offer Set Screw Couplings with a second set of screws at 90° This coupling is RC-075-KW Steel, Black Oxide Finish Rigid Coupling, 3/4 inch bore, 1 1/2 inch OD, 2 inch length, 5/16-18 x 3/8 Set Screw