For use with K-28829 in-wall tank and carrier system;Auto-flush technology monitors a person’s use time and determines if a 0.8 or 1.6 gpf (3.0 or 6.0 lpf) flush volume is needed;Large flush actuator plate is easily removed, allowing access to inner tank and flush valve for service;Two backlit flush sensors serve as a nightlight in low-light conditions;Manual backup flush button in the event of power failure