The EZ474SA is designed with the patented EZ Lock system making accessory changes 6X faster than using a standard mandrel Allows sanding of contours, details, and hard-to-reach areas Removes exterior surface layer without damaging the base layer below Built-in polishing compound: rubber bristles have abrasive inside; no need for polishing compound EZ Lock compatible, use with either Dremel EZ402 or 402 mandrels