Great addition to an air system, even if you aren't running lockers
"I recently installed a full ARB air system in my truck. I am not running lockers yet, just airbags, air horn, and a port for inflating tires. The outer plugs are 1/4NPT and the 2 center ones are 1/8BSP I believe. My twin air compressor goes into one of the outer plugs. I've got the pressure control valve with isolation valves in one of the smaller ports (no adapters needed) and I'll run another pressure control valve for the port in my bed. The outside 1/4 plug goes to my airhorn. I will need to reconfigure when I add lockers, but it's not going to be too difficult."