Size Arbor GRIT Maxrpm Type 4-1/2? 7/8? 36# 40# 60# 80# 120# 13300 T27 7? 7/8? 36# 40# 60# 80# 120# 8600 T27 Characteristics: Ideal disc for blending and finishing of pipe fabrications, vessels, tanks, enclosures or finishing of corner welds.Flexibility for blending and finishing on concave and convex curved surfaces,contours and profiles. Long life compared to resin fiber discs. Thread Hub available upon required.