Deluxe quality undersink 4 stage reverse osmosis water purifacation system.The WT4000 comes with a 50 gallon per day membrane,1 x membrane housing,2 x Pentek quality housings,1 x0.5 carbon filter,1 x 1 micron sediment,1 x 5 micron carbon final filter, 1 x QF longreach faucet,1 x 3.5 gallon steel holding tank,1 x housing spanner, 1 x USA shutoff valve, 1x John Guest check valve, JG quick connect fittings through out, 1 x drain clamp, all brass fittings needed for installation and 1 x instruction booklet