1st Stage ( 5 Micron Sediment Filter ) 2nd Stage ( 10 Micron Carbon Block ) 3rd Stage ( GAC Carbon ) 4th Stage ( Reverse Osmosis 50 GPD Membrane ) 5th Stage ( GAC Polishing Carbon ) 6th Stage ( UV Disinfection Sterilizer ) 7th Stage ( PH Correct Calcite / Mineral Filter ) Custom Designer Faucet with Teardrop Base. Manual Membrane Auto Flush Stage. In-Line Dual TDS Tester for Feed and Product Monitoring. Custom Aluminum Frame with Dual Pressure Gauges. Private and Custom Labeling per Request. Food grade Poly Tubing. RO-4 3.5 Gallon Storage Tank. NSF Approved Components.