ULTRAflex, 6 Pack, Medium, Fine Assorted Pack, Sanding Sponge Diablo’s Premium Ultraflex Sanding Sponges Include BreakThrough Innovations That Improve Performance, Extend Sanding Life And Increase HandSanding Productivity Featuring A Premium Aluminum Oxide Blend, These Foam Sponges Remove Material Faster And Offer Up To 3X Longer Sanding Life Versus Standard Hand Sanding Sheets Ultraflex Foam Technology Allows Flexible, MultiProfile Contour Sanding In Hard To Reach Areas The Full Contact Design Provides Maximum Sanding Potential By Delivering Consistent Scratch Patterns And UltraSmooth Finishes The Superior Grain Bonding System, ENDURABOND, Provides Diablo’s Sanding Blocks With Longer Life And Extreme Durability