When one labeling head is off-line for label and ribbon replenishment, the second head is triggered for immediate operation--resulting in zero downtime.  A stainless steel cabinet protects both units from harsh or wash-down environments. Each unit is mounted on a swivel mechanism that allows the unit to swing out of the cabinet for easy service and maintenance. To protect the tamp assembly the cabinet is fitted with removable covers. Covers are stored inside the cabinet doors when the units are in operation.