The front freewheel system was used with Shimano's "Positron" indexed shifting system. Unlike modern indexed shifting, the indexing was done at the derailleur. The front freewheel allowed shifting even when the bike was coasting. The rear "freewheel" wasn't really a freewheel, but a stack of cogs, each of which could turn independently. No ratchet in the rear; just a friction coupling on each cog to help prevent chain jams. The system was marketed toward low-end, entry level bikes for inexperienced riders, but was not enthusiastically received and disappeared from the market after a few years.