Zirconia Flap Discs: 1. Zirconia material 2. 24#-120# 3. 4", 4.5", 5",7". ... one step, thereby, reducing both finishing time and finishing costs. Zirconia flap disc for use on steel. Aluminum turbo flap disc ... "7/8"P600-P120012000T27, T297"7/8"P600-P12008600T27,T29 Zirconia Flap Discs