Universal standard size Geekpure supreme quality water filters are universal industry standard size and fit most residential Reverse Osmosis Systems and water filtration systems. Total is 5 pieces filters in the box. 1 x PP sediment , 1 x Granular Activited Carbon , 1 x Carbon Block Filters 1 x 50GPD Reverse Osmosis Membrane 1 x Inline Post Coconut Carbon. And 2 X1/4″NPT quick fittings and 1 Roll Teflon seal tape for post carbon filter. PP-Sediment Filter It is the 1st stage of Reverse Osmosis System. Function: Removes dust ,sand, silt, dirt, and rust particles in water. Specification: Micron Rating: 5µm , Dimension:10×2.5inch , Operating pressure:30-100psi , Temperature:33-100°F , Service life: 6-12 Months . Granular Carbon Filter It is the 2nd stage of Reverse Osmosis System. Function: Removes the chlorine, taste ,odors, cloudiness, colors organic matter, odor, smell turbidity. Specification: Micron Rating: 5µm , Dimension:10×2.9inch , Operating pressure:30-100psi , Temperature:33-100°F , Service life: 6-12 Months . Carbon Block Filter It is the 3rd stage of Reverse Osmosis System. Function: Further removes residual chemicals, odor and suspending particles, ensure purity. Specification: Micron Rating: 5µm , Dimension:10×2.7inch , Operating pressure:30-100psi , Temperature:33-100°F , Service life: 6-12 Months . Reverse Osmosis Membrane It is the 4th stage of Reverse Osmosis System. Function: High Rejection RO Membrane Removes up to 99% of contaminants including arsenic ,lead, fluoride, heavy metals and much more. Specification: Micron Rating: 0.0001µm , Dimension:1.8×12 inch , Operating pressure:45-250psi , Temperature:33-100°F , Service life: 15-24 Months . Post Coconut Carbon Filter It is the 5th stage of Reverse Osmosis System. Function: Removes any possible residual taste & impurity from the tank. Specification: Dimension:10×2 inch , Operating pressure:30-100psi , Temperature:33-100°F , Service life: 6-12 Months . Feed Water Specification: FEED WATER PRESSURE: 40 – 100 PSI , TEMPERATE:40-110°F/5-45°C , PH:3.0 -11.0 , MAX TDS :1000 PPM , TURBIDITY < 1.0 NTU , MAX SDI <4.0 , HARDNESS < 5 GPG , Shelf life: 3 Years . More valuable information: 1. What is dimension of the Geekpure Replacement Water Filters? If not Geekpure, the filters is available to other brands Ro water purifier? Answer : 3 x prefilters is 2.5"ODx 10" height,1 x membrane is 1.8"x12". the post carbon filter is 2"x10", all is standard size. Please don't worry. it compatible to most Ro system which its 10inch standard sized undersink ro systems . 2. What is 5 stage filters and functions? Answer : the 1st stage: PP spun filter, Remove sand, dirt, sediment. life time:6-12months. the 2nd stage: Granular activited carbon filter, Remove chlorine, taste & odors, very fine particulates. life time:6-12months. the 3rd stage: Barbon block filter, Further remove chlorine, taste & odors, very fine particulates. life time:6-12months. the 4th stage:Reverse Osmosis Membrane, High Rejection RO Membrane Removes up to 99% of contaminants including arsenic ,lead, fluoride, heavy metals and much more. life time:15-24months. the 5th stage: Post inline acid washed coconut carbon filter, Polish water for refined taste. life time:12months. The Life Time of the Filter Cartridge Depends on Usage Amount and Feed Water Quality. 3. What is in the box? Answer : 1 x PP sediment ,1 x Granular Activited Carbon ,1 x Carbon Block Filters, 1 x Reverse Osmosis Membrane and 1 x Post inline Coconut Carbon. And 2 x 1/4"NPT quick fittings ,1 Roll Teflon seal tape for post carbon filter. Reverse Osmosis Replacement Filter Cartridges Set for Ro System-2.5"x10"- Pack 4 Geekpure 5-Stage Reverse Osmosis Replacement Water Filter Set w/ 75 GPD Membrane Geekpure 5-Stage Reverse Osmosis Replacement Water Filter Set w/ 100GPD Membrane