The by-k4 from boya is a universal adapter from 3.5mm trrs to usb-c. You can use this adapter cable to make recordings with an external microphone. The microphone connects to your smartphone via a usb-c port. In the optional accessories you will find various microphones. On one side the adapter is equipped with a 3.5mm female jack connector (trrs). Connect the 3.5mm male jack connector of the microphone you are using to this. On the other side, the cable has a usb-c port that you plug into your smartphone. The adapter cable has a length of 60 mm. Compared to other cables on the market, you benefit from a thicker cable and therefore have a lower risk of cable breakage. Application boya by-k4 you can use this adapter to use your smartphone with usb-c port with an external microphone. Thanks to the small size, you can easily take the adapter anywhere. This way you can always interview or report live in unexpected situations. This makes the boya by-k4 an indispensable, affordable accessory to have with you at all times. Optional accessories also include other adapters, including trs and lightning connectors.