I've had this stove for twenty-five years. Quarter century and still going strong. Nothing has broken and no parts have ever been replaced. The design is simplicty itself and it is a well deserved cult classic. If you have one you grow to love it and keep coming back to it. Even though it weighs a little more than some modern designs, it packs really small and has a bomb proof reliablity. When your bivi-ing far from home that reliablity is what counts. This is the "R" model which has a built in nozzle cleaner to clear any soot build up. If you run it on Coleman fuel/petroleum spirit (white gas to Americans) I find this is never a problem anyway. It will run on unleaded petrol but then things do get messy and you have to clean out the tubes after a few months use. The easiest way to do this is by soaking the parts in petrol - the valve key is actually the spanner for taking the stove apart. If you want a good explanation of how it works look up SVEA 123 on Wikipedia.For an ultralight bivi stove try this: http://www.youtube.com/watch?v=n4WQV3p_nuM