Stage 1 – Sediment Filter Standard size: 10″ x 2.5″ 5 micron high-capacity (if you need 1 micron, 10 micron, 20 micron, 25 micron or 50 micron sediment filter, please leave a note when placing your order). Remove larger particles, dirt, silt, rust, sand, etc. Protects and extends the life of the membrane and system. Recommend replacing every 6 months (varies depending on the water source quality). Stage 2 – Carbon Block Filter Standard size: 10″ x 2.5″ Remove chlorine, tastes, odors, VOCs, pesticides and herbicides, etc. Recommend replacing every 6 months (varies depending on the water source quality). Stage 3 & Stage 4 – 150 GPD RO Membrane Filter Standard size: 2″ x 12″ Reject impurities down to 0.0001 microns, it can efficiently remove up to 99% of over 1,000 contaminants from your water, including heavy metals (primarily fluoride, calcium, magnesium, lead, colloids, chromium, and nitrates), organic, rubber mass, harmful minerals and another soluble salt from water. Recommend replacing every2~3 years (varies depending on the water source quality). 100% Safe: Membrane Solutions filters have been certified by NSF, ISO9001 and WQA. 100% Compatible: The replacement water filter combo pack compatible with Hydro-Logic Reverse Osmosis Purification Systems, such as Hydro Logic Stealth RO150, Hydro Logic Stealth RO300, Hydro-Logic HL31035 Stealth, Hydro-Logic 31040 300-GPD. Disclaimer: This product is a generic item that is designed to replace the original part. Any brand names or logos are the registered trademarks of their respective owners. Any use of any brand name or model designation for this product is made solely for purposes of demonstrating compatibility. Package Includes: 4 x Sediment filter 4 x Carbon block filter 2 x 150 GPD RO membrane filterOn Sep 13, 2023 at 03:21:58 PDT, seller added the following information: