Not all the tractors would have had one. It is for a double unit hydraulic and would have been used to raise and lower the cultivator on the left side. I know when I worked at the dealership probably less than 10% of the tractors had them even if they had a double unit. They would mount on the left fender. The right cylinder would be set up to be used on the implement you were pulling. Then later on you got into situations where some tools used two trailing cylinders and then when the 1800 came out both cylinders hung on the back of the tractor.