[Nut Dimensions]: Nut Shaft Diameter: 10mm .Nut Shaft Length: 4.5mm [Bolt Dimensions]: Bolt Head Diameter: 8mm .Bolt Head Length: 6mm [Usage]: Used for universal single chainring/chainwheel to fix the crank and chainring. [Application]: Fits for mountain bikes, road bike, folding bike, fixed gear bike, downhill bike, track bike, MTB, BMX, DH, etc [Material]: Made of aluminum alloy, lightweight, stable, durable, and not easy to crack or rust. [Package]: Includes 5pcs single chainring bolts kit, available in black and red. [Note]: Use 5mm inner hexagon spanner to install the bolts. Part Type Chainring Screws For Bike Type Mountain Bike Colour Black/Red Material 7075 Aluminum Alloy Quantity 5PCS Brand Unbranded/Generic MPN TJ4894670354718 .