Pad Saver- Hook and Loop. Available in 125mm and 150mm.

Mirka Pad savers are designed to protect your sanders backing pad from wear and tear. These pad savers are placed between the backing pad and sanding disc, and should be changed regularly. Pad savers prolong the life of a backing pad. Available in 125mm and 150mm. The 125mm has 33 holes (for efficient dust extraction), and the 150mm has 67 holes. Will fit most sanders.