Hi nick,I know when I put my gauges in the thread on the senders is 1/8npt and also I k ow that the thread on the original senders on The mk2 are 10mm as I was going to replace the oil temp sender on the back of the block with the sender that came with my gauge,In the end I used a sandwich plate between the oil filter and the oil cooler which has now given me three 1/8npt outlets.