The Double Stuff is a 303F and 303M bonded together and packaged in a leather pouch offering a variety of sharpening options. This pocket stone fits in the palm and has both medium and fine grits packaged in a leather carrying case. Use them dry, without oil, water or lubricants. For cleaning: scrub with a scouring pad, powered abrasive cleaner with water, and let them air-dry. Stones are autoclave safe (ideal for dental tool sharpening).