Material: Aluminum alloy; Connection Diameter: 12mm to 8mm ; Total Length: 30mm /1.2 inch; Outside Diameter: 25mm/ 0.98 inch Zero backlash. One-piece metallic spring coupling. For little torque shaft connect. Absorption of parallel, angular misalignments and shaft end-play by spring action. Widely used in drive systems for encoders, instrumentation,lead screws, small pumps, feed rollers and anywhere light to medium duty, torsionally flexible coupling is required. Package Content: 1 x Shaft coupling