Compatible APEC Ultimate Complete 5 stage high capacity filter set for model RO-90 3/8” RO-HI RO Reverse Osmosis systems FILTER-MAX-90-38 3/8", 100% compatible + instructions and free tech support, provided by Alton Filter Commercial grade, Contractor’s Choice 1st stage: Multi-layer 5 micron Sediment filter for more dirt holding capacity and extended service life. Dimension 2.5” diameter, 9.84” length” , standard size Fits standard 10” filter housing canister Made with Pure Polypropylene, no BPA Conform toe ISO 9001:2000 Manufacturing standard Removes sediment, dirt, sand, rust Replace every 12 months 2nd & 3rd stage: Activated coconut shell carbon block for extra capacity 5 micron rating 6,000 gallons chlorine reduction capacity or 2,000 gallons RO water usage capacity Dimension 2.75” diameter, 9.84” length Activated carbon block filter made with 100% high quality coconut shell carbon. Removes sediment, chlorine, chloramines, taste, odor, THM, VOC, Pesticide, Herbicide, turbidity Replace every 12 to 18 months Better bonding and structure designed minimize channeling effect and extend service life 4th stage TFC-100 similar to MEM-90 standard size RO membrane designed to fit the same membrane housings Dimension: 1.75” diameter, 2” diameter with seal x 11.74” length, standard size Fits standard RO membrane housing canisters High quality membrane material supplied from USA manufacturer. 95% rejection rate, improved structure designed for greater efficiency and extended service life Consistent performance Replace every 3 to 5 years 5th stage Omnipure inline carbon filter is 2”x10” with coconut shell activated carbon for final polishing and improving taste of water. Dimension: 2” diameter and 10” length, standard size Inlet / outlet are 3/8" quick connect fitting Improves taste, remove odor Replace every 12 months