Additional Details ------------------------------ Product description: SPECIAL HIGH FLOW version - 61452-10 Main Piston Standard for Fleck 7000 Softener Valve 35 GPM ( rare larger commercial application ). *Do NOT Order this Piston unless your are 100% sure it's the size / part number you need. The part number for the common Softener Piston = 61453-10. This product is part number 61452-10. NOTE: Filter applications ( non-water softener ) may require = Main Piston FILTER 35 gpm Fleck 7000 61452-20.