With a Franklin Sensors stud finder, you have the fastest, easiest, most accurate stud finder on the market. To operate the ProSensor M155, simply press and hold the button then place it on the wall and go. There is no calibration procedure. You can instantly find studs. Once you have it on the wall, the LEDs show you right where the stud is. The M155 has an Enhanced Precision LED display. With 15 tightly spaced LEDs the M155 more precisely identifies studs. When you move the unit back and forth, the ProSensor M155 continues to track the location of the stud which makes it easy to instantly see the edges and the center of the stud. Franklin Sensors stud finders are the most accurate stud detectors because they have more sensors. Other stud finders typically have only 1 or 2 sensors. The M155 has 9, making it the best wall stud finder on the market. With Franklin Sensors' patented technology, you can find stud positions with unbeatable accuracy. The wide display on the M155 allows you to see the full width of objects such as single studs and double studs. The M155 also identifies live wires for extra safety. The ProSensor M155 is the perfect wall scanner for many projects ranging from hanging pictures to installing cabinets and flat screen TVs. Once you try the ProSensor M155, Franklin Sensors stud finders will quickly become your favorite.