Can stretch and contract freely. Low friction loss, if installed correctly, will not leak. Easy to install. Simply extend the exhaust hose to meet the existing hose, align it at both ends and snap it into place. Made of high quality materials with good flexibility, durability and portability. It is not easy to break after prolonged use. Ideal for when the air conditioner is still running well, the necessary exhaust hose is broken and then you need to replace it.