【Usage】4335 is used in the humidifier, and has a water supply pipe, which is connected to the solenoid valve and then connected to the water distribution plate at the top of the equipment. 【Applicable models】 are suitable humidifiers for fit Aprilaire 400, 400A, 400M, 500, 500A, 500M, 600, 600A and 600M. 【Package】 includes # 4004 in-line filter and # 4231 yellow well plate. compression sleeves and compression nuts are also included. 【High quality】 These accessories are made of high quality materials and are durable. 【After-sales】 If you have any questions, please feel free to contact us by email, and we will reply you within 24 hours and give you a satisfactory answer. The 4335 Is Used Inside The Humidifier And Contains A Water Supply Pipe That Is Connected To A Solenoid Valve And Then To A Water Distribution Tray On Top Of The Device. For Models 400, 400a, 400m, 500, 500a, 500m, 600, 600a And 600m. Includes #4004 In-Line Filter And #4231 Yellow Well Plate. Compression Sleeves And Compression Nuts Are Also Included. Maintenance Kits #4788 (400 Series), #4792 (500 Series), And #4839 (600 Series).