Radium Fuel Pressure Regulator, with No Top Radium Fuel Pressure Regulator, with No Top If a regulator top is not needed (already have one from another source), select Radium 20-0014. This option includes everything needed with the exception of the regulator top. If a regulator top is not needed (already have one from another source), select Radium 20-0014. This option includes everything needed with the exception of the regulator top.