Description: The rigid coupling has a 90 degree mounting structure and is fixed by four machine screws. Widely used in motors, equipment, molds, mechanical transmissions. Specification: Material: aluminum alloy Color blue Length: 25mm Outer diameter: 14mm Type: 5mm-5mm,5mm-8mm,6mm-8mm,8mm-8mm (optional) Screw hole diameter: 4mm Transfer hole diameter: multiple specifications Quantity: 2pcs Suitable for 3D printers, clutches engine, ship models, car models, airplane models etc. Package include: 2 pcs x coupling Note: 1. The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness.2. Please allow slight manual measurement deviation for the data.