Tips: Please confirm the shape and size of the back outlet of the air conditioner before purchasing. This adapter fits square exhaust vent measuring 5.9“ x 7” (150mm x 180mm) and connected to a 5.9” (150mm) diameter exhaust hose. （It is not universal, please confirm the compatibility with your AC unit before purchasing） Enhanced Cooling: This adapter can connect the exhaust hose closely to your a/c unit to prevent leakage effectively, quickly discharge hot air, cool the room soon, save electricity and reduce energy consumption, an essential accessory for our 5.9 inch air conditioning vent. Wide Compatibility: This exhaust hose tube connector fits on the back air outlet of many portable Air Conditioner units. The square end is attached to the air conditioning exhaust port, the round end is connected the 5.9" diameter exhaust hose. The round end is featured with universal thread design, fits both clockwise and counterclockwise exhaust pipes. Premium Material: The AC exhaust adapter is made of high quality ABS material, thick, sturdy and durable, can be used for a long time. Easy to Use: No tools needed, no drilling. Connected to the exhaust hose, and then attached to the back air outlet of the portable air conditioner. The AC exhaust vent hose connector tightens the vent hose to your air conditioning unit, there will be no leakage, making your air conditioning unit more efficient and cooling your room in less time.