Replaces conventional dryer vent hoods. Floating shuttle is designed to remain closed unless dryer is in use. Positive seal keeps cold or hot air out as well as unwanted pests. Made of ABS plastic. Off white in color. Can be painted to match the home. Installs using 4″ pipe. Vent measures 13″ H. x 6-1/2″ W. x 7″ D.