The Xiaomi MiKey is an intelligent shortcut key for Android devices. It's a small button mounted on a 3.5mm headphone jack, which you plug into your smartphone. It will have 10 different, programmable functions, including being used to turn on the phone's flashlight, or-slightly dubiously-record phone calls. https://www.zapals.com/genuine-xiaomi-mikey-anti-dust-plug-quick-shortcut-key-3-5mm-plug.html