We have 10 IBC tanks around the farm and they have several different types of connectors. My favorite ones have male cam locks right on the valve. Some have NPT threads and for the odd ball ones I just put a Fernco style rubber fitting on it and put a cam lock end on them. On those I also put a second valve on them because the design of the valve with those tanks is terrible. I can get those fittings at my local hardware store and have not had a leak in the last 4 years.