The Unger Heavy Duty 15" x 16" Microfiber cleaning cloth sets the standard. This cloth is available in four colors and is manufactured to withstand excessive (up to 1,500) commercial washing cycles (three times more than the Light Duty microfiber cloth). Please note that this is the Heavy Duty microfiber cleaning cloth with the highest quality grade textile and maximum absorbency compared with Unger?s other microfiber cloths (Light Duty, Medium Duty, and Heavy Duty). Red cloths are used on toilets, bidets, and urinals, yellow cloths for all other areas of the bathroom, green cloths are for the kitchen and blue cloths are for all other areas in the house. The SmartColor Cleaning System help prevent cross-contamination (restroom cloths remain in the restroom and kitchen cloths remain in the kitchen).