61555 - Fleck 2900s Lower NHWBP Piston
ONLY for model 2900s (single casting 1 piece control valve body)
Does NOT fit in the older style 2900 (2 piece casted control valve body)
NHWBP = NO HARD WATER BYPASS – The unit will not provide any water to service when it goes into a regeneration cycle. This type of piston is typically used in twin or multiple tank systems.