Style-Line's Soft-Sanders are thier unique solution for sanding hard-to-sand areas such as curves and rounded edges. Soft-Sanders are made of varying densities of foam that is still soft enough to compress into hard-to-sand places. Soft-Sanders will conform to your sanding surface while maintaining the necessary curvature. Soft-Sanders feature soft, rounded edges that virtually eliminate gouging; tapered edges for better access to difficult areas; and are durable and colvent-resistant. Becuase Solft-Sanders are so lightweight and comfortable to use, you experience zero fatigue! This set comes with 6 blocks and 3 pieces of Super-Flex sandpaper. The 6 blocks come in 3 different densities, and each is a different shape. Best used with adhesive-backed sandpapers.