Petcock, fuel valve, with 3 positions: on, off, and reserve. Specifically for Ambassador, 1969 to 1972 V7 Special, Eldorado and 850GT fuel tanks, these can also be used on V700 fuel tanks but if you are using the original steel generator covers the right side lever must be shortened slightly to clear. The manufacturer claims these valves are resistant to 10% ethanol, but obviously, ethanol will damage the rubber so we recommend avoiding it.
Note: Due to the variety of fuel additives on the market, different environmental conditions, and multiple fuel additives being used today, we no longer offer free warranty replacements on these valves. We have these on motorcycles here in Wisconsin that have been in use for over a decade.
Note 2: Installation tip: Some people have reported that the internal gasket has turned with the handle when these petcocks are new - in order to prevent that, we suggest spraying a lubricant into the valve and working the valve back and forth prior to installation.