Package Includes - 1/2 \"-80 Sanding Rings + 4 Sanding Drums; 3/8 \"-80 Sanding Rings + 4 Sanding Drums; 1/4 \"-80 Sanding Rings + 4 Sanding Drums; Total 252 Pieces Used for smoothing curved surfaces and edges, polishing soft and hard materials such as DIY, artwork, and wood products. Easy to Install - The mandrel comes with a self-expanding rubber cushion, which holds the sanding band tightly close to the mandrel and achieves a better finish; if the sanding band falls off the mandrel during use, make sure the drum is tight and very close to the sleeve. Note: Wear professional safety glasses to protect your eyes, as there may be clump particles when the sanding drum rotates at high speed; the sanding drum will be adsorbed on the metal surface faster, replace the sleeve in time to achieve the best sanding effect. Comes with a free plastic box for easy storage and access.