Excellent web-site, telephone customer service, shopping-cart system & checkout process, fast shipping. The product I bought, a 7" coarse-grit S-shape tooth concrete grinding wheel, worked excellently for my purpose which was removing a slippery surface finish on a standard 2000-2500PSI outdoor patio concrete area. Approximately 80 square feet gone over twice, plus 4500 deep edge-grooves (using only ~15º radius of the wheel, up on edge,) made relatively light wear on the wheel. Estimate over 80% of the carbide+diamond grit teeth remain for future projects. Highly recommended.