The Window Cleaning

Any of a variety of types of telescopic poles, fitted at the upper end with a brush and water jets, fed either from vehicle-borne tanks of deionised water or by on-site production of deionised water using a domestic or commercial water outlet. The water is filtered by either a two-stage or three-stage filtration process, involving a carbon filter, and two de-ionization filters, or a carbon filter, a reverse osmosis membrane filter, and a de-ionization resin filter. The filtered water contains a TDS (total dissolved solids) of less than 5 ppm.