1Special Design: 3.5mm selector, specially designed for customers with multiple sources and outputs, without power and drive, easy to use. 21 Source: Choose 1 speaker or earphone, (1 input source choose 1 output to earphone or speaker to avoid frequent replacement of earphone or speaker causing damage). 34 Sources: Choose 1 speaker or earphone, (choose 1 out of 4 input sources to output to the speaker or earphone to avoid frequent replacement of sources). 4Support 1 Output Input: The 3.5mm stereo switcher only supports 1 output input selection, and cannot support 4 outputs inputs at the same time. 5Compatibility: The 4 port 3.5mm stereo switcher is compatible with all devices with 3.5mm output ports, such as mobile phones, laptops, computers, MP3, MP4, headphones, active speakers, etc. Item Type: Converter Material: Aluminum Alloy Colour: Black Size: Approx. 78 x 55 x 21mm/3.1 x 2.2 x 0.8in Interface: 5 x 3.5mm Headphone Jack Frequency Range: 20Hz-20KHz Parameters: Two Way Switching Splitter Sharing Active Speakers and Headphones (Cannot Be Output at the Same Time), the Analog Signal Supports Up to 2V P P Input and Output One Key Mute, Convenient and Fast, Very Practical in Special Occasions Plug and Play; No External Power Supply Required; No Impact on Sound Quality at All Compatible with Various Earphones and Speakers, etc. 1 x Converter 1 xCable 1 x Manual Please allow 0.1& 8209;0.2cm/0.04& 8209;0.08in error for manual measurement