Which Pulsator Do I Need?

There are actually 3 different Surge Vacuum operated pulsators. The "S" style goes with the older lid that doesn't use an o-ring. The "C" style goes with the newer lid that uses an o-ring on the post The "C" and "Siphon" have clean-out plugs on the bottom side. The "Siphon" pulsator was used on the early pipline breaker cup milkers. It's the same as the "C" style except the post is shallower and will not fit the bucket milker lids.