Dual-function valve cartridge maintains a consistent water temperature from one shower to the next. Monitors water pressure to balance temperature. All Delta tub and shower faucets are engineered to keep the water temperature within a safe +/-3.6 deg F (+/-1.7 deg C). This technology makes sure your family doesn't experience a sudden and possibly unsafe change in water temperature as a result of running water elsewhere, such as using a dishwasher, flushing a toilet or running a washing machine. The valve cartridge features an adjustable handle limit stop that, when properly set, helps ensure the handle cannot be turned to a position that is too hot for comfort. Easily replaced seals make maintenance a snap. This cartridge is included with tub and shower trim packages. Requires inlet water temperature be set correctly. May require seasonal adjustments.