Whirlpool 11.74-in Under Sink Replacement Filter with Reverse Osmosis by Whirlpool 11.74-in Under Sink Replacement Filter with Reverse Osmosis. Fits many standard reverse osmosis systems including Premier, Omni and GE. Water permeation: 50 gallons per day. Product does not fit Whirlpool WHER12 and Whirlpool WHER18 reverse osmosis systems.