Spyderco's Double Stuff sharpener 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. It is autoclave safe (ideal for dental tool sharpening) or can be cleaned with a plastic scouring pad and powdered abrasive cleanser. Measures 1" X 5" X 1/8" (25mm X 127mm X 3.2mm)
Information from Spyderco