From the Manufacturer: Byte Brothers tools exhibit 3 qualities: Innovation- It moves our company and our customers forward. Top quality- work requires tools that repeatedly perform. Affordable- Tools are useless unless you can afford to buy them. Byte Brothers guarantees these 3 qualities plus offers US based customer support, training and quick upgrade and warranty service. Whether you are in the catacomb, telecom, audio/video. electrical or security field, you will find Byte Brothers products designed for you at a price you can afford. Product Description: All Low Voltage Pro Models generate tone for locating cables. The tone is compatible with most tone probes (if you already have one).