Features 1、Used for blocking position for the shaft and steel wire. When installing the wheel, use the wheel block to lock the inner limit or the periphery of the wheel to lock the steel wire or the landing gear axle. When the wheel is rotated, it does not run off and detaches, which plays a fixed role. 2、Pattern edge makes the knob rotation easier. 3、Carbon steel hex fixed buckle, can be used repeatedly without breaking. 4、Appearance plating process, no rust, no scratch. 5、Including 10 pcs shaft collar to meet your quantity needs. Specification Item Type:Shaft Collar Material:Electroplate Ferronickel Type: Inner Diameter:4.1mm/Outer Diameter:9mm/Thickness:5mm/Weight:2g/M3 Locking Hole Inner Diameter:5.1mm/Outer Diameter:10mm/Thickness:5mm/Weight:2.4g/M3 Locking Hole Inner Diameter:6.1mm/Outer Diameter:10mm/Thickness:5mm/Weight:2.4g/M3 Locking Hole Inner Diameter:8.1mm/Outer Diameter:12mm/Thickness:5mm/Weight:2.6g/M3 Locking Hole Package List 10 x Shaft Collar 1 x Hex Wrench