Flap Discs OPTIMAflex. Application: due to special technical characteristics recommended particularly for surface grinding for steel,stainless steel, non-ferrous materials, wood. Suitable for sanding, bevelling, surface grinding, edge grinding, preparation and cleaning. Thanks to flat radial arrangement of abrasive lamellas they reach higher performance and have a longer operational life than other instruments. Discs are made of layered zirconium 100% cotton segments resin-bonded to a fiberglass backing plate.