Feature:1. The ni gear here is able to mount on a shaft without the need for a hub.2. Constructed of hardened steel and mount with two set screws for excellent hold on 8mm shafting.3. The bore perfectly matches 8mm shafting to create a positive drive, simple installation.4. Using highhardness material, and sturdy, wearresistant, longterm use.5. With 8mm hex hole, exquisite workmanship, it is a practical industrial robot accessory.Spec:Item Type: GearMaterial: Cast SteelProduct Model: 4303-4008-0030Product Specifications: 8mm / 0.31in hex hole 0.8 modulusOuter Diameter: Approx. 25.6mm / 1.01inPitch Diameter: Approx. 24mm / 0.94in Package List:1 x Gear