One of Joseph-Armand’s pivotal inventions was the sprocket wheel track traction system. The toothed gear drives a rubber track, giving vehicles better traction in difficult terrains. To manufacture the sprocket, he first had to build a pattern. This one is made of steel, wood and wax. It was used to shape a sand mold and then to cast the metal. According to the inscriptions on the pattern, this was a model for the C18 snowmobile—a larger version of the B12 that could accommodate up to 25 passengers.