[Durable Material] coupling connector is made of fine plating steel, heat and electroplated process make it sturdiness and insulation, striking shaft more stable and easy for installment and replacement. [Wide Range of Use] flange coupler is produced based on Flange Standard, widely used in model shaft connection, perfect accessories for RC Model motor. [High cost performance]flange coupler is packaged with 4 pack 8mm Flange Shaft Coupling + 4x Mini Hex Wrench + 8 x Fastening Screw. [Standard Specification]Inner Diameter: 8mm. Cylinder Outer Diameter: 10mm. Cylinder Height: 10mm. Base Diameter: 22mm. Base Height: 2mm. Color: Silver Material: Stainless steel Package Contents: 4 * Flange Coupling Connector 4 * Mini Hex Wrench 8 * Fastening Screw Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.