RO DI BYPASS KIT REALLY SIMPLE TO INSTALL SAVE BIG $ Extend the life of your DI by up to 80% longer. When any reverse osmosis system first comes on, the TDS level of thewater produced by the membraneissubstantially higher thanitwill beafter about45-60 seconds of water production. So in an effort to extend DI cartridge life open the DI bypass valve first, leave it open for 45 seconds or so and then open the pure water line, close the DI bypass and start making RODI water. You are simply skippng the DI stage and sending the product water to drain while the DI bypass is open. Excellent product and simple to install. Comes with everything you need to install the kit in 5 minutes. Works on all membranes any size. All 1/4" fittings and tube. Save several DI changes per year! "kit pays for itself and keeps on saving!"1 - Tank Shut off valve1 - 1/4 inch T fitting1 - 1/4 inch inline Shutt off valve 6- Feet of 1/4 inch tubing DETAILED INSTRUCTIONS