I believe BSP. I added two VDO 52mm gauges to my console. Water temp was straight forward. Wire in as per diagram and used the existing water alarm sensor for both functions. Oil pressure requires replacement of the sender unit from a single contact to a dual type. Marine and automotive are the same. I suggest 0-5bar (0-70psi) so the needle will be in the middle of the scale when in use. Raph.