1. This trainer has two working modes. It can be used for CW training on computers and mobile phones. It is compatible with various operating systems and supports plug-and-play functionality without requiring additional drivers. To use this trainer with a mobile phone, an OTG adapter or OTG cable is required. 2. USB interface: Connects directly to a computer or mobile phone via an OTG device. 3. Key interface: Supports connection to manual keys and electronic keys. To connect a manual key, attach the key first, then connect the device to a computer or mobile phone. The trainer automatically detects the connected key type. 4. Mode button: Switches between Mode 1 and Mode 2. Press and hold the button while connecting to a computer or mobile phone to toggle modes. In Mode 1, pressing and holding the button moves the cursor downward; continuing to hold after reaching the bottom of the screen causes the cursor to move upward from the bottom — a feature optimized for mobile use. 5. LED indicator: Shows current operating mode. A solid light indicates Mode 1, designed for mouse-controlled CW training software or apps such as LCWO, CWPlayer, and Morse Trainer. A flashing light indicates Mode 2, intended for specific CW training tools including those used with VBand, MorseMania, and MorseIt. Name: CW Key Trainer Specification: USB interface Color: Green Material: Plastic Package Contents: 1 × CW Key Trainer Note: The package includes only the item listed above. Other accessories are not included. Note: Color appearance may vary slightly due to screen settings and lighting conditions. Dimensions are subject to a tolerance of ±1–3 cm.