Estate 4000The Estate 4000 is designed for the largest spaces and strongest odors in homes, condos, and offices. This model has a variable ozone output control and a 12 Hour Timer that turns off automatically when the treatment is completed. For deeply entrenched odors, there is also a Hold setting for treatment longer than 12 hours until the machine is turned off manually. A good selection for large houses, large condos, large offices, rental properties,