Features: High sensitivity and strong penetration power, significantly improved sound quality. Can be connected to a display, spectrum analyzer, recording pen, transmitter, wireless equipment, etc., and can also be inserted into a two-channel cable for direct recording. Durable and lightweight for easy carrying. Easy to operate: stick to a door, window, or wall, and adjust the sound with the knob until you hear a clear sound. A great tool for listening through wooden, brick, or concrete walls, windows, and doors. Effectively filters noise and detects sounds faster. Specifications: Color: Black Current consumption: 12mAh Probe sensitivity: 60dB Working time: 5-7 hours Battery: 3.7V 100mAh Item size: 37 * 34 * 27mm / 1.5 * 1.3 * 1.1in Item weight: 25g / 0.9ounce Package size: 93 * 80 * 37mm / 3.7 * 3.1 * 1.5in Package weight: 73g / 2.6ounce Packing List: 1 * Voice Listening Detector 1 * Headphone 1 * USB Cable 1 * User Manual