Climax Metal 1C-031-S T303 Stainless Steel One-Piece Clamping Collar, 5/16" Bore Size, 11/16" OD, With 4-40 x 3/8 Set Screw Effective on hard and soft shafts Design fully engages the shaft without any marring Provides 360 degree of clamping force Easily installed where major disassembly would otherwise be required T303 stainless steel is effective in corrosive environments