This is a pack of four replacement Tekno RC M5 Serrated Flanged Locknuts. These are used with TKR5570B M5 threaded stub axles for the SCT410, but can also be used anywhere an M5 serrated locknut is required. These nuts will ensure your wheels stay on your vehicle. M4 serrated locknuts simply can’t compare and can strip or come loose much easier than an M5 nut. Features: Massive M5 thread and serrated back ensures your wheels will stay on Less wasted wheels due to stripped out wheel hexes Larger thread is more durable and will last longer than any aluminum M4 nut Aluminum construction is light weight Black anodized for wear Note: Requires an 8mm nut driver or socket for installation. Most glow plug wrenches will work here.