Power Supply Voltage: DC-5V via Type-C Output Port: 3.5mm jack Operating Temperature: -40C to 85C Principle:The touch key is divided into two layers. The upper layer houses the key's main circuitry and interface, while the lower layer houses the magnetic base. The device uses chip to sense changes in the capacitance of a metal ball. When a person touches the metal ball, the capacitance change is transmitted via circuitry to the relevant pins on the chip. The corresponding key signal is amplified, driven by a transistor, and finally transmitted to the key interface. The device's logic is to indicate a low level for a valid key signal and a high level of 5V for a non-touch signal. This voltage level matches the operation of most radios. The lower layer contains a strong magnet that can attach to any metal casing, securing the key. Instructions:The USB cable can be connected to a mobile phone charger or computer. Please note that the USB port must be powered by 5V; other voltages damage the chip. After powering on, the LED at the USB port light up, indicating proper power supply. If you touch the left or right metal ball, you see the corresponding LED light up. At this time, the touch is valid and the product functions normally. The touch button on the right is short, representing one point, and the touch button on the left is long, representing one stroke. Color: Red Material: Stainless Steel+ABS Package Contents: 1 x CW automatic keyer 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.