5" waterproof C weight paper sanding discs. Super sharp and fast cutting Silicon Carbide abrasive. Individually cut discs with Pressure Sensitive Adhesive (PSA) - each disc includes a protective release liner that provides for maximum adhesion and prevents grit, dust and air from degrading the disc's backing. Used for wet sanding on natural and engineered stone, plastic, fiberglass and concrete and glass. High quality German industrial abrasives factory direct.