MSR XGK, old style, from 1981 to 1994. There are variations on this - mine has the generator wrapped in wire like this example, early release versions are not. Mine was also this clean - once upon a time.... and there is this the MSR XGK II with 'shaker jet". and this the MSR XGK EX - whow! The stove has an interesting history and soon replaced the SVEA 123() as the 'must have' stove for outdoor use. One of my rock climbing buddies had an original "Model 9" the daddy of all what followed. Here is a concise history of the stove with years made and variants. On line tests have shown the older XGK has a slightly higher heat output, but both sound like an Atlas rocket in heat when fully fired up. I don't know of a more accepted or better stove for heating water/melting ice at altitude. The stove was known in the climbing community the Mountain Safety Research eXpedition stove for white Gas or Kerosene - hence the XGK. Frankly, if it is liquid and will burn, the XGK will burn it. The XGK-EX is a stove that does one thing very well, and that is melt snow. It is very durable and easy to maintain. It is also expensive at $160 for new. The stove is fuel efficient, and produces high BTU output at altitude. It also will not simmer, it simply was not meant to do that. This is an expedition stove, not a backpacking stove. Having said that, I got mine for two reasons. To melt snow and to use any fuel I might be able to obtain in Bush Alaska. The burner has two orifice (tips) one for Gasoline and one for kerosene/diesel. I know many aircrew types that packed one of these in their RON bags. Eating cold rations is no fun in the snow. It works the treat on JP-8, and many were seen in the sandbox. There was - or a limited time - a military version (different paint) I would note that just as many or more of the Coleman Exponent Multi-Fuel Stove were floating around as well. At $110, almowst as expensive as the MSR. Pros: Melts snow in a hurry. Will burn damn near anything. Easy to fire up - for this type of stove. Cons: Not a real lightweight stove. The fuel tubes are rigid. Until the XGK EX came out, the biggest failing of the system was the fuel fed tube. This is partly an engineering issue, the tube has a metal cable inside to help control flow. The XGK EX has a flexible feed. The feed tube cannot be disconnected from the burner unit. This makes carry/packing a PITA. The pumps on the newer units just plain suck. Not that older pumps were all that great - both were made with plastic parts that become brittle with age and use. Life gets very interesting if your pump comes unglued while the stove is lit.... This is, IMO, the biggest point of failure in the system, notwithstanding the rigid feed tube in the older models. . There are clone (better) pumps on the market - if you find a stove a thrift store or garage sale All require a specialty fuel bottle You cannot adjust the flame very well - mostly all the way on or off. Eye wateringly expensive, if you are just needing a backpacking stove. Make no mistake, these stoves are still the Gold standard for extreme outings. If you aren't going to climb K-2, then any number of other MSR stoves may fill the bill at less cost. Trivia: The XGK windscreen was a radical departure at the time of introduction and is still the key to fuel efficiency. This is also why the fuel bottle is separated from the burner. The same style windscreen is used on other MSR stoves, all with separate fuel bottles. Just like a Barbie or an expensive boy toy - the XGK has a number of solid accessories: Spares kit (red box) - buy it with the stove, this is a no-brainier! Ditto on a spare pump body if heading out of country. The metal gizmo with holes is a snow support leg kit. Ya. Above the treeline - nice to have but a metal food plate will work as well. Close up of spares kit The stoves are stupid simple to maintain and fix with a single tool. Tearing one down and reassembling - with a burn to check operation while in a nice warm workshop with a bench and good light is always a recommendation of mine to new owners. You will be doing this in the field, might as well get it down pat and doing it right in a non-stress situation. This actually applies to just about every piece of gear you will carry. Evolution of the burner over time/model type. There is no lack of full documentation for the system, MSR and their vendors are very good about this. Have fun.