Windows cleaning is included in Maintenance fees so strata of the building hires them for windows cleaning of the entire building.
The job is done very poorly, last time they forgot to clean one window and the worse thing they do every time they come they empty their buckets with dirty water and detergent in front of windows (main floor) in planted garden area. They do not care to finish their job in a professional manner. I would never hire or recommend them. They may be less expensive than others but they do poor job on a very unprofessional level.