A flush valve includes a body having a water inlet and a water outlet. There is an inner cover mounted on the body and with portions of the flush valve defines a chamber which is in communication with the flush valve inlet. A sensor for detecting the presence of an object adjacent the flush valve is mounted on the inner cover, as is an electrical circuit for causing operation of the flush valve. There is an outer cover which encloses the inner cover, sensor, and electrical circuit. The outer cover is formed of a plastic which will transmit radiation from the sensor whereby the sensor can detect the presence of an object adjacent the flush valve. The inner and outer cover have interfitting lugs which restrict relative rotation therebetween and provide a means for attaching the covers to the flush valve body through the use of a ring which applies a load only to the inner cover.