Zirconia Flap Discs: 1. Zirconia material 2. 24#-120# 3. 4", 4.5", 5",7". 4.Original Manufacturer Flap discs and wheels grind and finish in one step, thereby, reducing both finishing time and finishing costs. Zirconia flap disc for use on steel. Aluminum turbo flap disc disc for use on aluminum. Ceramic flap disc for use on stainless steel.1. T27,T29 Abrasive Flap Discs2. Backing: plastic cover, ...