Velcro attachment is a popular attachment method for polishing and grinding wheels that allows for quick and easy wheel changes. Discs with this system have a Velcro fastener on the back that easily attaches to the corresponding counter on the sander. This type of attachment is very useful for jobs where the discs need to be changed frequently for different grit levels, which is typical for example when progressively grinding from coarser to finer. This system is valued for its efficiency and time saving.