Ultraflex Ultra Fine & Micro Fine Assorted Pack Sanding Sponge (6-Piece). Diablo's Premium Ultraflex Sanding Sponges Include Break-Through Innovations That Improve Performance, Extend Sanding Life And Increase Hand-Sanding 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, Multi-Profile Contour Sanding In Hard To Reach Areas. The Full Contact Design Provides Maximum Sanding Potential By Delivering Consistent Scratch Patterns And Ultra-Smooth Finishes. The Superior Grain Bonding System, ENDURA-BOND, Provides Diablo's Sanding Blocks With Longer Life And Extreme Durability.