The HD series is a light commercial product that is manufactured by Cyclovac. Since the HD units are custom units, they can be made to have either two or three stage motors, the single motors are also larger in diameter for greater air flow or water lift.
The unique part about the HD units is they are motor only, so they can be combined into 1-2 or even 3 units in a row to create “custom vacuum application”. These units must be attached to separators, since they don’t have any capacity for filtration of dirt. The warranties are the best in the industry, 950 hours (these units feature an LCD display which counts the hours of motor usage) of run time or 15 years; which ever comes first!
Another great option with these units is separating the vacuum unit from the separator, so they main HD unit could go into a mechanical area for noise, and then the dirt receptacle can (separator) go into another area for easy disposal of dirt.