Tecomec grinding wheels are 5-3/4" in diameter with a 7/8" arbor, designed to fit most Italian (Maxx, Oregon, Tecomec, Speed Sharp) and Chinese (Carlton, TimberTuff, Northern Tool) chain grinders. These wheels are made of vitrified aluminum oxide, which holds its shape fairly well, even under high heat. They will eventually lose their shape, and will need to be reshaped with a corundom grinding brick.