Culligan AC15 AquaClear Reverse Osmosis Filter Set (not including membrane) This set of filters for the Culligan AC15 includes the following filters: The Culligan compatible RS-23-SED5 Sediment Filter (5 micron filter for screening out sand, silt, dirt, rust and any other physical particulate). Culligan compatible part numbers are 01-4015-38, 00-0001-20, 4412-75, 4496-27, S7011C, 4485-44, 4496-27 The Culligan compatible pre-reverse osmosis carbon block is the second stage of the AC15 RO system. It is responsible for taste, odour and colour and protects the membrane from chlorine. Culligan compatible part numbers are 01-0125-80, 00-0011-38, 01-0042-91, 01-0000-78, 4027-96, 4487-63, 4496-28, 4487-62 The Culligan compatible K2333-KK 3/8" inlet and outlet post filter is the 4th stage of the Culligan AC15 System. It is a polishing filter for the system. The Culligan compatible part number is 01-0042-91