This is a very high quality brake master cylinder. This is for the 1941-48 jeeps. This is what some people call “the short one”. This has one threaded mounting hole and one non-threaded hole. This is a single reservoir system. IMPORTANT…please measure the distance between your mounting bolt holes on your original. These are 3 1/8″ from center to center. Also remember 1948 is a transition year from the CJ2A to the CJ3A and a different size master cylinder.