pin slotExplore our hh-quality product portfolio and confure the part that is rht for you. Ball Lock Pins, Slot Pins - mech from MISUMI confurable & free CAD download. Buy from MISUMI,4 pin fans can run in 3 pin fan slots and will only go in one way since the header is keyed but will only run via voltage control. Most fans don't mind but have slhtly less range of