Marketing InformationThe ND Series of ultra-zone dampers was designed with the installer and homeowner in mind. This damper is easy-to-install and easy to checkout. The LED display allows the installer to visually check the damper operation. With a sturdier frame, the damper installs in the duct much faster and easier and the nylon bushings insure quieter operation. This is a feature that homeowners will never hear about quieter operation and a longer life motor equals NO call backs.