If one wanted a true historical system, what would it be?There are number of things involved in Peterson System. P-lip and water trap are just two of them. Other two are narrowing of draught in the stem from tenon to the button, and extension of tenon below the draught in the shank. All these work together to remove moisture from the pipe and collect them in the trap. It works fine and some notice drier smoke. But is it necessarily better? That's up to the individual smoker.