Weiler Tiger high performance premium zirconia alumina/ceramic infused 4-1/2 inch resin fiber discs deliver a fast, consistent cut rate.4-1/2 Tiger Zirc RFD 100Z Grit 5/8-11 UNC The superior design extends disc life by optimizing grain shedding and promotes cool grinding on steel and stainless steel. A superior design extends disc life by minimizing grain shedding and promotes cool grinding on steel and stainless. Long life and fast cut.