This product is a battery-powered clip-on LED lamp designed for use in experimental and research settings where portable, low-power illumination or text display is needed. It operates only when the connected battery voltage exceeds 3.0 V, with a rated voltage of 5 V; insufficient voltage leads to unstable lighting. The lamp can display up to four Chinese characters or four English letters simultaneously. It is important to note that the lamp does not include a battery or a USB charger, and direct USB charging may damage the display. The device is available in red, blue, and green variants. Typical applications include material testing, signage, or as a visual indicator in laboratory fixtures and equipment setups where battery clip connection is practical.