Gator, 3 Pack, 45 x 78, 36 Grit, Aluminum Oxide Fiber Discs, Designed To Be Used On Angle Grinders With A Backer Pad For Aggressive Sanding Of Metal, Fiberglass Painted Surfaces, For Used With 45 Backer Pad 3017, Resin Bonded To Resist Heat Humidity For Longer Life