Work Sharp Standard Replacement Kit for the Ken Onion Edition Mk.1 and Mk.2 (WSSAKO81113). Official listing is one 3/4" x 12" belt of each grit: P120, X65, X22, X4, and 6000. Official page states the belts are formulated and made in America by Norton for Work Sharp Ken Onion sharpeners. Weight 1.6 oz. Specs from the worksharptools.com Standard Replacement Kit for the Ken Onion Edition (Mk.1 & Mk.2) page.
The cassette-size belt pack. Same five belts that ship with the Ken Onion Mk.2.