Mocal OT2F in line oilstat oil thermostat that is placed in the flow and return oil lines.
It has -8 AN male ports.
When oil temp is below 80 degrees centigrade the unit allows a least resistance oil return - the bypass is open.
When oil temp is above 80 degrees centigrade the bypass closes and ensures oil is circulated. These are often used with oil coolers, however can be applied to various oil control applications