United abrasives – sait 27610 challenger iii grinding wheel type 29 4-1/2 ” x 1/8 ” x 7/8″ 36 grit type 29 flexible grinding/blending wheel, semi-flexible. Grind and blend welds in one step. Open pattern on wheel for cool grinding and blending. Contaminate free – safe for use in the nuclear industry. Requires no backing pad.