This is a EAG1311200 5.5x9x1200 Wet/Dry Sheets. Eagle Silicone Carbide Flexible Back Waterproof Sheets. The world's most reputable wet sanding paper for it's durability, speed & extremely uniform abrasive grains. Sharp silicone carbide abrasive grains. Sharp silicon carbide abrasive grains. Sharp silicone carbide abrasive grain is resin-over-resin bonded on a highly flexible anti-slip backing which requires no pre-soaking before sanding.