A WFP or Waterfed Pole is a pole that has a hose running up it that is attached to a brush. This can be anything from an unger extension pole fitted with adapters to allow it to accept a brush and hose, about $100.00 or so all the way up to many thousands for other types of poles. Materials range from Aluminum to fiberglass to carbon fiber, carbon fiber being the most expensive typically.
Water is transported up the hose to the brush to clean the window.
Not just any water will do. You have to have purified water to do the job correctly. Purified water means that you remove all the minerals in the water. By removing all the minerals in the water you will have no spotting when the window is dry. How you remove the water is an imporant aspect to obtaining pure water. You can spend a couple hundred dollars achieving this or a couple thousand. This all depends on the water quality in your area and your desire to use it daily VS. monthly.
The method in which you clean the window with the WFP is simple. You brush the entire surface(while water is flowing through your brush head) then after the entire surface is brushed /agitated you follow up with a rinse. This can be done by lifting one side of the brush off the glass or by rinsing with the brush on the glass with certain brushes.
Any other questions feel free to ask or give me a call anytime and I can explain things to you one on one.