Do I have an SB330 (3000 PSI) or SB600 (5000 PSI) model accumulator?

If the model code or part number cannot be readily located on the unit or any associated paperwork, you must inspect the gas valve stem on the accumulator itself. If the diameter of the gas valve stem at the point where it comes out of the shell is 7/8'' (22 mm) then it is a SB330. If it is 2'' (50 mm) then it is a SB600.