Greenback™ Maxidisc™ - Pearl's Trimmable Flap Discs with 5/8-11 Thread QUICKMOUNT™ EASY TRIM BACKING SAVES TIME AND MONEY! Greenback's™ nylon Easy Trim backing allows you to shave off the green backing as the flaps wear down exposing more flap length. This translates into fewer wheel changes, saving you down time thus reducing your product usage and labor cost. Non-warping nylon back Reinforced with fiberglass, gives the Greenback™ flap disc more strength and durability than the competitions plastic back even under the most severe conditions. Combination polyester/cotton flap The best zirconia grains, on a special combination polyester/cotton flap, hold the grain more securely and resist clogging. Less vibrations Polyester/cotton flaps cushion the backing thus reducing vibration and noise. Easy grit identification Never wonder what grit you are putting on your grinder. Even after extensive use you can still identify the grit. Runs cooler Exclusive outer coating, over the best premium Zirconia grains available, make the Pearl Abrasive Greenback™ Maxidisc™ flap disc run cooler and last longer as well as providing lubrication to prevent burn marks and discoloration of the finished material.