AIR PRESSURIZATIONThis shower faucet set features innovative air technology where the rain shower head mixes water with air, increasing water pressure to 100% and simulating natural rainfall to provide you with a natural contact water experience. CONTAINS cUPC CERTIFICATIOINThis shower cartridge is cUPC certified, the shower system meets local US safety certification installation standards and can be installed with confidence. The shower valve kit has two built-in check valves to reduce water noise. SPECIAL DESIGN Hot and cold water connector external straight threaded pipe easy to weld, electrician welding no longer worry about the internal straight threaded pipe will be clogged. check valve can be adjusted with a screwdriver to adjust the size of the water pressure, counterclockwise adjustment of large, clockwise adjustment of small (default is the maximum water pressure), adjusted to the minimum water pressure can be turned off. HIGH QUALITY MATERIALSThis shower head