The odds of finding a model # 50 boiler wandering around by itself are not very high. In fact this is one of only a couple we know of that ever went out in public as solo acts. To add to the mystery, the boiler has a unique configuration of heaters.  The typical 5 inch model 50 boiler of this era had 2 ceramic heaters located in dry wells within the boiler tank. This one has an additional "blanket" style heater similar to those used in our electrically heated hobby engines, along with many of our older black box style boilers. This would have required quite a bit of customization of the heater. We are of the opinion this was a special order for a specific project the customer had in mind. A nice find by an highly observant collector with a fast Ebay connection.