Merit Abrasives High Performance Mini Flap Wheels with 1/4"-20 Thread Premium ceramic and aluminum oxide abrasive grain for aggressive cutting and longer life. Heavy cotton backing designed for superior wear resistance. Designed with a 1/4-20 in steel shank as an integral part of each wheel for better balance and quick change without the need of special tools. Flap wheel design and flexibility of the material leaves a finer finish grit than other coated abrasive products. Pack of 10