Features: Experience unparalleled portability with our CW Key Practice Device, making it for your pencil case, backpacks, or pocket. Power by a CR2032 battery, this device eliminates the need for external power sources, offering months of use. Perfect for both beginners and enthusiasts, this practice tool provides auditory and visual indicators through a beeping sound and a LED light, enhancing rhythm understanding and individual styles visualization. Use it from home to outdoor setting, suitable for diverses environment. Compatible for various manual key types, including vertical hand key and horizontal paddles key, this practice device ensures seamlessly operate and mastery of any Morse code techniques. Specifications: Component:PCB Size:Approx.26x24mm/1.02x0.94inch Package Includes: 1pc Morse Key Trainer 1pc CR2032 Battery note: Please allow 1mm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual item color.