Power options: operates on AAA batteries (not included) or via USB cable. In external power mode, you can connect a DC power source to replace the battery supply; the unit automatically switches from battery to external power without removing the batteries. When unplugged, it resumes operation from battery power by pressing the button. Battery not included (three AAA cells). Adjustable Clips: clips grip objects of different thicknesses. A small rotatable tail piece on the clip can be turned independently to expand the clamping range and ensure a secure grip on items. Arms and build: light arms are made of quality metal alloy for strength and flexibility. They can be set in any position and adjusted to the required angle and shape, providing a full range of lighting and multi angle options. Brightness and controls: the LED lights attached to the battery operated clip on lights are as bright as three standard LEDs. Switches on the dual arms support four configurations: one light on (single arm), one light on both arms, two lights on the single arm, or all lights on both arms. No flicker, shadow, or glare, designed for reading. Use scenarios: - Night reading in bed or on the sofa: clip to a book or tablet and adjust the angle for comfortable illumination. - Desk study or craft work: attach to a notebook or pattern and direct light where needed. - Kitchen or workshop hands free tasks: clip to a recipe book or instruction sheet while keeping your hands free.