This is a retro mobile phone receiver that allows you to be more comfortable when answering calls. More suitable for people who communicate on the phone for a long time The Telephone Handset has 3.5mm Round Socket;Handset Size:21*6*5cm cm/8.27*2.36*1.97'(LxWxH);Cable length:1M/3.28FT You can adjust it according to your needs, with a 1-meter extension cable, you can easily answer calls Steps of intallation:1. When there is a call on the mobile phone, use the Telephone Handset plug to point the hand socket;2. Press the answer button Only works with 3-channel 3.5mm audio socket,before purchasing, please confirm the size of plug