Standard with 1″ connections. Appropriate size wholehouse water purifier for high daily and/or incidental volume demand or high sediment applications. Also comes with pre-filter as pictured in the non-auto backwash models above (e.g., IL9). This pic to emphasize the Fleck 2750 auto backwash valve. Rated for 1,000,000 gallons of flow-thru service life and capable of accommodating up to 12 gpm flow-thru.