Features: 100% Brand new and high quality Perfect for installing, debuging, maintaining telephone line and other wires or cables. Detect continuity of the cables or wires without damaging the insulation Track the cables or wires, and diagnose the break point. Receiver the tone signal on the cables or wires (telephone line). Identify the state in the working telephone line (clear, ring, busy). Send a single solid tone or a dual alternating tone to the object cables or wires. Include a sender (MS6812-T) and a receiver (MS6812-R). A profeional & safe tool for wireman. Order notice: The performance of the Blue and Black products is exactly the same, the difference lies in the color and model. Specifications: Send tone frequency: 1.5kHz Receive frequency range: 100 ~ 300kHz Power supply: 6F22 9V (Not Included) Receiver size: 23.8 x 4.3 x 2.6cm Emitter size: 14.5 x 3.5 x 2.5cm Shell Color: Green Net Weight: 233g (Approx.) Packing List: 1 * Sender. 1 * Receiver. 1 * Toolkit. 1 * Instruction Manual. 1 * Color box. Excellent workmanship: Tool Kits FWT21 product and X1 EBTN display 3-in-1 Smart Voltage detector multimeter