Correct flat top brake master cylinder for pre 1965 Cooper S. Originally the top of this master cylinder would have had either a removable union or a small hexagonal nut shape machined into it, but neither of these options are available so the pipe goes directly into the flat top as per normal but the outlet is period correct. The later master cylinders have a more pointy shape where the brake pipe comes out. 3" high canister as opposed to std Mini 2.3/8".