This is a new type of digital signal finder, it has a b anti-interference function to any current or magnetic field and other external environment, fast and accurate line checking speed, whether with or without load can be accurate positioning, communication lines, wiring and other weak current system installation, maintenance engineering and technical personnel of practical tools. Widely used in telephone system, computer net work and metal wire lines and other fields. Specifications: Material: ABS Power Supply: DC9V 6F22 battery (NOT included) Max. Working Current: Transmitter: 20mA; Receiver: 30mA Signal Transmission Format: Multi-frequency pulse Signal Output Level: 8Vp-p Signal Distance: 3km Model: MY6815 / MY6816 (Optional) MY6815: Item Size: Emitter: 126 * 48 * 33mm / 4.96 * 1.89 * 1.30in Receiver: 175 * 40 * 23mm / 6.89 * 11.57 * 0.91in Item Weight: 124g / 4.38oz Package Weight: 235g / 8.29oz Package Size: 22 * 15 * 4.5cm / 8.66 * 5.91 * 1.77in MY6816: Item Size: Emitter: 147 * 57 * 28mm / 5.79 * 2.24 * 1.10in Receiver: 178 * 46 * 26mm / 7.01 * 1.81 * 1.02in Item Weight: 157g / 5.56oz Package Weight: 268g / 9.45oz Package Size: 22 * 15 * 4.5cm / 8.66 * 5.91 * 1.77in Package List: 1 * Receiver 1 * Emitter 1 * Clip Line 2 * Network Cable 1 * Tool Bag