Accessories: Cush Drive Housing-2pcs Stainless Steel Round Head Screw 3x10-3pcs Stainless Steel Flat Head Screw 3x10-3pcs Manual number: 7793X Product major function & usage: Gather and stabilize the gear for better performance Major advantages of upgrading to this product: 1. Made with a quality light weight high tensile strength aluminum 6061 T6 for greater durability and more sturdy use. 2. Minimize the gap between the gear and the cush drive housing, which improves the stability and makes the transmission more powerful.