You're looking at a very special item.
This is an original item from the 1950s. This K&O #108 electric motor is just what you have been looking for to put in that vintage boat. K&O advertised that this motor was best with small to medium sized boats such as 12"-15" boats.
The electric motor unit footprint is 1 1/4" x 3/4" x 1 15/16". It runs 3-6 volts dc. Nickel plated (looks chrome) and gray. It has a built in bracket for easy mounting. The total unit weighs 3.5 ounces. Based on the data in the old K&O paperwork I believe this motor to be catalog number 108.
It is not one of the more common models that you see.
If you collect vintage model or toy boats, this is one of those things you have to grab when you see it this clean.
CONDITION: C-7++/-8. Tested and works. The chrome part of the casing is still nice and shiny. It is hard to get good pictures of shiny chrome like nickel, but it is very shiny and nice. Does not appear to have been used much if at all. Pictures show it all. No box.