OBSOLETE - No Longer Available.
Large Lower Piston Assembly for the Fleck 2930 and 3130 valves.
This is the HWBP ( Hard Water By Pass ) version.
Meaning it allows hard water to flow past the valve while the system is in regeneration.
NOTE: Many "Commercial" applications require the NHWBP ( No Hard Water By Pass ) version of this piston to prevent any water getting past the system while it is regeneration.