Four-stage reverse osmosis drinking water system for fresh tasting, clear drinking water. Membrane options include 36 gpd, 50 gpd, or 75 gpd. Reverse osmosis membrane reduces total dissolved solids (TDS) by 96%. Top quality coconut carbon post-filtration provides final polishing for the freshest taste. Compact design saves under-the-counter space. Manufactured in the USA. Product benefit: Reduces Chlorine External testing certification: WQA Item weight: 5.0 pounds Material: Plastic The Sierra 4-stage reverse osmosis system delivers gallons of clean, clear drinking water. Choose from 36 gpd, 50 gpd, or 75 gpd membrane options. e Sierra features hygienically sealed filter cartridges and color-coded fittings for easy installation and service. When properly maintained, the Sierra system will provide you with years of trouble-free service. e cartridges in this system must be replaced on a regular basis to maintain efficiency and to ensure high water quality. Test your water every 6 months using a digital TDS meter. Consider membrane replacement when the TDS rejection falls below 85%.