Super torque can absorb vibration, appropriate a large torque transmission. Wear resistant, high hardness and excellent response. Mainly used for servo motors, spindle, step motor etc.. NOTE:The shaft coupler is not elastic, can not modify the concentricity. Shaft must be located in a straight line. If your equipment is eccentric already, then it will make noise and cause off-centering.Please be cautious before your final purchasing, thank you. Specification:Type: Plum ShapedSize: 35 x 30mm/ 1.38 x 1.17 inch( L*D)Bore Diameter: 8mm to 14mm/ 0.31inch to 0.55inchMaterial: Body: Aluminum Alloy; Sleeve: PolyurethaneMain Color: Silver Tone, Red Package Content:1 x Plum coupling.