Diablo's Premium Dual-Edge Sanding Sponges Include Break-Through Innovations For Superior Sanding Performance, Extended Sanding Life And Increased Hand-Sanding Productivity. Featuring A Premium Aluminum Oxide Blend, These Dual-Edge Sanding Sponges Remove Material Faster And Offer Up To 3X Longer Sanding Life Versus Standard Hand Sanding Sheets. The Sanding Sponge's Dual-Edge Creates Concave, Edge And Bevel Profiles With The Use Of One Sponge. 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.