1. B:USB interface: You can connect the computer through a mobile phone power cable, or you can connect the mobile phone through a data cable with dual B:USB interfaces. This trainer has built-in OTG circuit, so there is no need for OUG conversion. 2. Electric key interface: You can directly connect 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 intelligently identify the hand key or automatic key. 3. Button: Used to switch between mode one and mode two. and hold this button to connect the computer or mobile phone to switch between the two modes. In mode one, this button can move the mouse logo. This function is especially important on mobile phones. Pressing and holding this button can move the mouse logo downward. Move to the bottom of the mobile phone screen and continue to hold this button, and the mouse logo move upward from the bottom. 4. Indicator light: Indicates the working status of the two states. The indicator light is always on in mode one, which is suitable for training software or APP operated by mouse, such as for Lakey, for Cwplayer, for MorseTrainer, etc.; the indicator light flashes in mode two, which is suitable for some special training software or APP, such as for Vband website, for MorseMania, for MorseIt, etc. Colour:P o Color Material:plastic Package Contents: 1 x CW Trainer Morse 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.