Uxcell a13052700ux0319 6.35mm to 8mm CNC Stepper Motor JAW Shaft Flexible Coupling Coupler Product Name: Beam Coupling; Features: Set Screw Type(Coiling Clamping) Shaft Usage: 6.35mm to 8mm / 0.25" to 0.31";Length: 32mm / 1.25" Diameter: 25mm / 1";Material: Material Aluminum: Aluminum; Color: Silver Tone Weight: 37g;Package Content: 1 x Beam Coupling