1、One Touch Answer Button: Wired telephone adopts one touch answer button, press it to answer or hang up the call. 2、Volume Control: Wired telephone can use the cell phone volume control slider to adjust the listening volume. 3、Sound Switch: The old school phone has an sound switch to further improve compatibility with different brands of smartphones. Works with most smartphones. 4、5mm Sound Plug: The wired telephone has a 5mm sound plug that is compatible with a wide range of smartphones on the market. 5、Superior Performance: Wired telephone features retro styling; reduced cell phone radiation; superior sound quality; 9 feet coiled cord for added flexibility. 1 x Retro Telephone Receiver    Item Type: Retro Telephone ReceiverMaterial: ABSCompatibility: For All Smartphones and Computers with a 3.5mm Headphone JackFunction: Support Hang up and Answer