Mini and Moke brake master cylinder 1980-1989 dual outlet (c/w adapter)
Genuine AP Lockheed boxed and made in UK. Front to rear master is the latest model dual master cylinders, which was introduced in 1985 with a stepped bore of 17.8 to 19 mm to replace any previous master cylinders from September 1978 to 1988 when the built in servo type master cylinder was introduced. One of the notable features is the failure switch on the reservoir cap with a yellow identification tab. This replaces all the front to rear square type reservoir cylinders. It should also be noted that this master cylinder has 2 different size metric unions, the top one is 10mm and the bottom one 12mm for the larger stepped bore size to the rear brakes. New pipe kits are required. 
Please Note: Bottom piston does rear brakes - upper piston does front brakes. Some master cylinder before this type were the opposite with bottom doing front and top doing rear.