It is used to detect optical fiber breakpoints, and is used in the construction and maintenance of integrated wiring, production and research of optical c-omponents and other optical fiber projects. Features: Lightweight and portable for easy carrying and comfortable hold. Longer penetration distance, stable performances and long service time. 3-gears brigtness adjustable, and there are power signal lights, pay attention to the power at any time. With LED light convenient for dark environment operation. 2.5mm universal pen heads, detachable, easy to replace the core. Specifications: Type: B3S05, B3S15, B3S20, B3S30 (optional) Output power: B3S05: 5mW B3S15: 15mW B3S20: 20mW B3S30: 30mW Working time: B3S05: 10h B3S15: 3.5h B3S20: 5h B3S30: 5h Interface: 2.5mm Output wavelength: 650nm Battery: B3S05: 2 * AAA battery, 1.5V, 250mAh B3S15: 5V, 900mAh B3S20: 5V, 900mAh B3S30: 5V, 900mAh Item size: 125 * 35 * 17mm / 4.9 * 1.4 * 0.7in Item weight: 56g / 2.0ounce Package size: 150 * 60 * 30mm / 5.9 * 2.4 * 1.2in Package weight: 83g / 2.9ounce Packing List: 1 * Fiber Optic Tester