1. This trainer has two working modes. It can be used compatible with CW training on computers and mobile phones. It is suitable compatible with various systems and is plug-and-play without drivers. If you need to use this trainer on a mobile phone, you need to prepare an OTG adapter or OTG adapter cable. 2. USB interface: It can be directly connected to a computer or a mobile phone through an OTG device. 3. Electric key interface: It can directly connect to the hand key and the automatic key. To connect the hand key, you need to connect the hand key first and then connect the mobile phone or computer. This device will intelligently identify the hand key or automatic key. 4. Button: Used to switch between mode one and mode two. Press and hold this button to connect a computer or mobile phone to switch between the two modes. In mode one, this button can move the mouse mark. This function is especially important on mobile phones. Press and hold this button to move the mouse mark downward. Move to the bottom of the mobile phone screen and continue to press and hold this button. The mouse mark will move upward from the bottom. 5. Indicator light: Indicates the working status of the two states. The indicator light is always on, which is mode 1, suitable compatible with training software or APP operated by mouse, such as compatible with Lakey, Cwplayer, MorseTrainer, etc. The indicator light flashes, which is mode 2, suitable compatible with some special training software or APP, such as compatible with Vband website, MorseMania, MorseIt, etc Name:CW Key Trainer Specification:USB interface Colour:Green Material:Plastic Package Contents: 1 * CW Key Trainer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.