I purchased these from FANTECH but sold the property I was going to install them in before I had a chance to install them. They are NEW AND IN BOX. I have them at other properties and THIS SET UP IS AWESOME. It drastically reduced drying time and improved dryer efficiency. If you are experiencing clogged dryer exhaust or your dryer is not drying as fast as you expect this may be the answer. I am selling them together because there is no reason for me to only have part of the set. I am selling them at almost full price because I am sure I will find a use for them otherwise. You would be helping me clear a space in my garage. DBF 4XL is a dryer exhaust fan. It helps your dryer run efficiently while removing the warm and moist air from the dryer duct. The fan should be added in the dryer duct run when the length of the run exceeds 40 feet with no bends, 35 feet with one bend or 30 feet with two bends. The fan can be used to effectively maintain dryer exhaust in duct runs up to 130 linear feet. The DBF 4XL features a pressure switch that automatically activates the exhaust fan once the dryer is on. The fan is equipped with a 5 feet cord with a plug for 120V/1~ power supply. Performance certified by HVI; safety certified by ETL to UL507. Some helpful tips to take into account while installing the dryer exhaust fan DBF 4XL: • Avoid using rigid PVC pipes or flexible ducts. Use only steel or aluminium ducts rated for dryer use. These ducts have smooth walls, so lint is less likely to build up. • If you are running your dryer duct through an unconditioned space, make sure you wrap it in insulation. If the duct stays warm, it will be less likely to form condensation and collect lint. • To avoid clogging lint over the exhaust fan impeller, install a secondary lint trap DBLT 4W. It filters the air, catches the lint and protects the fan and ductwork. The less lint accumulation, the better your dryer performs. DBLT4W Secd Lint Trap Item Number: 46000 When you think of serious hazards in your home, this one doesn't come to mind: lint. It's not a hazard to health, such as for example, mould or radon gas. Lint can light up fast, and can be a serious fire hazard. Lint in the ductwork can also self-ignite, given the right conditions. This risk increases the more lint accumulates in places it shouldn't, such as a dryer vent and duct. Taking proper precautions helps minimizing the risk. A good way to do this is by installing a secondary lint trap DBLT 4W between the dryer and dryer exhaust ventilator. The lint trap box is equipped with a screen that filters the air that feeds into the dryer exhaust fan. The screen catches any airborne lint in the ductwork that isn't caught by the dryer's lint screen. The less lint accumulation, the better your dryer performs. Even if you're cleaning the lint trap once a month, it's a good idea to look through its window to make sure the filter isn't full. The lint trap DBLT 4W is made of galvanized metal sheet and fits a 4 inch duct. The device can be used when the duct length between dryer and exhaust fan is between 5 and 15 linear