Check the listing for details. 3M 36248 321U Series Hook & Loop 400 Grit 6 in. Sanding Disc (50/Pack). Color: Blue, Condition: New. Listed at 50.37 USD. Our 3M Hookit blue abrasive disc 321U delivers best in class performance at every stage of paint prep and body repair. Premium aluminum oxide mineral abrasive is blended with ceramic grain for a full range of automotive sanding applications. Our multi-hole discs feature a specially-designed pattern that reduces loading, extends disc life and aligns with most backup pads. Hookit attachment makes disc changes easy. Features:A best in class abrasive sheet roll offering for the entire repair and paint preparation processEngineered ceramic mineral blend is balanced for maximum abrasive performance in its classDiscs available in multi-hole pattern for excellent dust extraction or in no-hole formatAnti-loading coating prevents dust and debris from clogging the cutting surfaceUpgraded resins improve durability and finishHookit attachment makes changing discs fast and easy