Bosch's metal-cutting abrasive wheels feature the X-Lock mount, offering a wheel change that's up to 5X faster than conventional interfaces. There's an audible snap when mounting an X-Lock wheel on an X-Lock grinder. The wheel mounts properly without the need for a spanner wrench or flange nuts. The wheel is released from the grinder with the pull of a lever. Bosch bonded abrasive wheels are made with high-quality aluminum oxide grit for exceptional speed and durability in tough environments for cutting applications.