Brake union 3 way,UNF. This Genuine AP 3 way connector was used on the diagonal split braking system joining the front brake pipes to the main line system on both sides of the car, hence 2 fitted. On later dual line cars, with the pressure valve on the bulkhead (1978 on), a single connector is fitted at the rear to feed the wheel cylinder pipes in place of the old type regulator valve. ERA cars also used one of these on the rear of their cars.