Features and Benefits: Blue Magnum with super strong phenolic resin as a bonding agent is simply the best! Couple this with flexible latex backing in an indestructible E-weight and the end result is one of the toughest longest lasting high performance coarse grit sandpapers ever made. High strength blue latex paper backing improves performance and flexibility and reduces curling and edge chipping Latest NorZon grain design improves cut rate extends product life and is self-sharpening New coating technique gives more consistent and uniform scratch pattern Re-designed bond system optimizes grain adhesion and extends product life