With mounted flap wheels, coated abrasive flaps are arranged radially around the core in a fan-like structure. The flexible flaps perfectly adapt to surface contours. The abrasive grain is embedded in the sturdy, flexible cloth backing material with a resinoid bond. In ISO 3919, mounted flap wheels are designated as "flap wheels with shaft." For coarse grinding work with a high stock removal rate and cool grinding. Active grinding additives in the coating substantially improve the stock removal rate, prevent loading and result in cooler grinding.