Stainless steel M12 with no nut. The robust vent allows any pressure retained within the enclosure due to temperature change to escape and not place any stress on your device's gaskets/seals, enhancing the life span of a product. Conversely, as temperatures reduce and the pressure within your enclosure starts to suck the outside world inwards, the vent allows that pressure to equalise saving the IP rating of your device. This vent is a serviceable part, it is quickly installed. The vent transfers air at a rate of 1600ml per minute at 7 kPa. Within the range there are other M6 or M12 vents with differing air flow rates. Typically, the lesser the air flow, the stronger the ingress protection.