This is Mirka's Gold Hook and Loop sanding discs in an assorted package. It is a durable product very well suited for sanding at high speeds. It has 10 each of 80, 100, 120, 150 and 220 grit.
Gold is an all-around sanding material that can be used for many purposes. In order to achieve an optimal sanding result, the semi-open grit binding and special stearate coatings are designed to prevent clogging and pill forming These hook and loop discs work on a wide variety of orbal sanders.