Wave Hi-Performance sanding discs are highly durable open-coat abrasives that remain bonded, resist loading, and stay sharp longer than the competition. Unique to the Wave system are their "wave" discs, with crenellated edges that flex smoothly and virtually eliminate swirls & sharp edge cuts on the inside of turnings. The discs mount directly on hook & loop sanding pads to work with exactly the degree of stiffness & resilience you need. Innerface pads velcro onto your sanding pads; sanding discs then velcro into the innerface.