2PCS 5mm to 6mm Aluminium Plum Flexible Shaft Coupling 25mm Length 20mm Diameter Connector Flexible Coupler for 3D Printer CNC Machine and Servo Stepped Motor: Amazon.com: Industrial & Scientific
Befenybay 2PCS 10mm to 10mm Aluminium Plum Flexible Shaft Coupling Diameter 20mm Length 25mm Connector Flexible Coupler for 3D Printer CNC Machine and Servo Stepped Motor(10x10mm): Amazon.com: Industrial & Scientific
Othmro SDA20 x 15 Sealing Thin Air Cylinder Pneumatic Air Cylinders, 20mm/0.79inch Bore 15mm/0.59inch Stroke for M5 Aluminium Alloy Pneumatic Components for Pneumatic and Hydraulic Systems 1pcs: Amazon.com: Industrial & Scientific
Amazon.com: Front Fork Barrel Shaft, 20mm to 15mm Front Hubs Tube Shaft Axle, Aluminium Alloy Accessories for Bicycle(100 Open Gear) : Industrial & Scientific
Amazon.com: HIGHER MEN Durable Aluminium Alloy CNC Stepper Motor Flexible Couplings Black Diameter 20mm Length 25mm Shaft Coupler Clamp Reliable Quality (Inner Diameter : 8mm to 10mm) : Industrial & Scientific
ALUMINIUM ROUND BAR/ROD 4,5,6,8,10,12,16,20mm diameter (in many Lengths) | eBay