Mirka Gold 5", 5 hole PSA disc with a durable aluminum oxide grain delivers a fast, long lasting cut. C & D weight paper backings are 50% stronger than competitive A-weight backings. This durable sanding material is well suited for high speed sanding in a multitude of applications. Gold features semi-open and special stearate coatings designed to prevent clogging and pill forming which helps achieve an optimal sanding result. This makes Gold the TRUE standard.