ITEM NAME:Wheel Hexagon Drive Hub Adapter Combiner Metal Coupler with Pin for HPI VENTP4E3 Wheel Hexagon Drive Hub Adapter Combiner Metal Coupler with Pin for HPI VENTP4E3 Made of high-quality metal materials, it blends perfectly with the climbing bike and is durable. Easy to install and remove, stable and rust-free. It is a very popular coupler replacement accessory that can upgrade RC cars. With 4 sturdy couplers, 4 screws. Type: Hex Combiner Hex: 12mm / 0.5inch Thickness: 8 mm Colour: Light Blue Material: metal Size: 1.3 * 1.3 * 0.7cm Package Contents: 4 x Hex Combiner 4 x screws.Type: Hex Combiner. 4 x Hex Combiner. Colour: Light Blue. Size: 1.3 1.3 0.7cm.