Comparing to normal faucets, the 3 way faucet is equipped with two separate internal channel , the main channel is still used as usual for mixer faucet water which is kept the desired  temperature via a ceramic mixer valve in the faucet, there is warm and cold water connection, in the second channel, on the other handle, the filter water flow, this is connected directly to OS and therefore the two channel's water do not contact for each other, the three way faucet with two separate levers for pured water and mixer water. and the three way faucets is connected via two flexible hose and pured water hose or quickly adapter.the two flexible hoses (normally blue and red marked ) conected to hot and cold water , the pured water hose or quickly adapter is connected to the osmosis system. The 3 way faucet can replace your older faucet by its hole, it is easy to replace and conviently for working