These wheels are made of nonwoven high density abrasive flaps, glued radials around a hard core, designed to resist demanding operations and high temperatures. The abrasive grains quantity is double than the other materials. Especially suited for stainless steel satin-glazing, but also excellent for wood and particularly resistant metal applications. Special surfaces effects on gold and silver. Measures 4" diameter x 1 1/4" thick. Arbor hole measures 1/4". The higher the number, the finer the grit.