Those things are freakin awesome! When I worked as a road mechanic for Hyster forklifts one of my customers was a heavy equip. engine rebuilder and he showed me one that had doors so you could walk inside it.
*walk nonchalantly into a parts house* "yes yes, im after some 15W-40 oil, what one is less expensive? oh yea the delo-400? ok, im going to need about 7500 gallons, you can get it here by tomorrow right???"