These are our own brand of white aluminium oxide vitrified grinding wheels. They are a general purpose wheel suitable for sharpening high speed steel (HSS) tools and grinding most steels. They offer cool and burn free cutting and excellent wheel life all at a very competitive price.All with 31.75mm bore, supplied with 1", 7/8", 3/4", 5/8" and 1/2" bore nylon bushes.All York grinding wheels are supplied in a unique storage box, which helps prevent chipping and other accidental damage. Spare cases available.Type 1: Straight grinding wheels.Note: Truing recommended before first use.