Aeroflow's Universal roll over valve can be screwed directly into an Aeroflow Fuel cell that has a -12 female thread. The top of the valve has a -8 ORB female thread and a stainless steel ball. It can be used with the AF996-12D, AF996-12S and AF996-12SS weld-on or an AF924-12 Bulk Head nut with a choice of any -08 ORB to suit any plumbing solution. When the fitting is screwed into the top of the roll over valve, it locks the ball.