The EBD (Electronic By-Pass) style are self-contained units that give you the static control mounted to the damper. It is an "all-in-one" design that makes the installation process much easier than most electronic by-pass dampers. The static pressure can be adjusted in the field between 0.5" to 4" of pressure. This is done by the turn of a set-screw. Requires 24VAC to operate. Tubing and pitot tube are included.