With a HART stud finder, you have the fastest, easiest most accurate stud detector on the market. To locate wall studs, simply press and hold the button, 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. When you move the unit back and forth, the HART Advanced continues to track the location of the stud which makes it easy to instantly find the stud center and edges. HART stud finders are the most accurate stud finders because they have more sensors. Other stud finders typically have only 1 or 2 sensors. The HART Advanced has 7 sensors, making it the best stud detector on the market. The HART Advanced is the perfect wall scanner for many projects ranging from installing towel and curtain rods to hanging pictures. Once you try the HART Advanced, HART stud finders will quickly become your favorite. The assembled product weighs 0.36 lbs. AAA Battery Powered: requires two AAA batteries (not included).