1. The 5-in-1 design is more powerful, more accurate and more durable. 2. This product can quickly and easily locate the wooden metal studs, joists, metal pipe reinforcement and live AC wires behind walls, floors and ceilings. 3. The alarm design allows you to always know the situation of the wall and make the operation more accurate. 4. SH402 wall detector can clearly identify what objects are inside the wall, which is more intuitive and accurate. Wood detection, metal detection, current detection. 5. It has a wide range of applications. You can use it whenever you want to view the interior of an opaque object. Use upgraded internal sensors. It can sense the change of space density behind the wall and locate the center of the stud very accurately. Model:SH402 Net weight of product:340g Alarm mode:beep Battery type:9V dry battery (delivered without battery) Display:LED LCD green backlight screen Colour:Silver Material:ABS Size:17.1x7x3.5cm Package Contents: 2 x SH402 detector Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.