For 1" thick bench grinding wheels. Arbor reducing bushings. Reduces arbor to multi-sizes: 1/2" (12.7mm) or 5/8" (15.88mm) or 3/4" (19.05mm). Plastic arbor reducing bushings Reduces arbor to multi-sizes 1/2" or 5/8" or 3/4" accessibility Reducing bushing adapter for 1" thick wheels. WARNING: Wash hands after use. Cance