There are no tubes, hoses, check valves, regulators, or proportioning tips to bolt on later. The shelf base provides increased stability, durability and safety. Patented, twin chambered, no-chemical contact inserts allow dual flow rates for easy filling of spray bottles or mop buckets. AccuPro Technology eliminates dilution variance at higher water pressure (up to 80 psi) and the installed back-flow preventer alleviates any water supply concerns.