What is this?Flange Coupling Connector is widely used in model shaft connection and is a great accessory for RC model motors.What will I get? Product Name: Flange Shaft CouplingColor: RedMaterial: Stainless SteelInner Diameter: 5mm/0.2 inchTotal Height: 15mm/0.6 inchCylinder Outer Diameter: 15mm/0.6 inchBase Plate Diameter: 28mm/1.1 inchBase Plate Height: 3mm/ 0.12 inchPackage Content:4 Pcs x Rigid Flange Coupling4pcs x Mini Hex Wrench8pcs x Fastening ScrewAre there any advantages of this product?Hardened by heat treatment and then electroplated. Durable and insulation, make your shaft more stable, easy to install and replace.How to use it?Flange Shaft Coupling can fix a shaft to a plane, and can easily install other accessories on the shaft. It is easy to install and replace.What should I notice?All size is measured manually, please allow +/-0.1 inches error.