The Wonder Junior Bicycle Sprocket Conversion Kit does the hard work for you. Hook your mill up to an old bicycle or exercise bike for simpler, mechanized use and save your shoulder! The fastest hand-crank mill on the market, it is strong enough to put up with a lifetime of mechanized use. The sprockets mean simple conversion that can be done or undone with each use. You will get your exercise and work up an appetite for your freshly milled bread!