Zircon HD900 9 Volt 4-Mode Multiscanner for Finding Studs, Live Wire, or Metal w/ Backlit Display (Battery Not Included, Tool Only) 4 MODES: Stud Scan lets you find studs up to 3/4 inch deep, Deep Scan lets you find studs up to 1 1/2 inches deep, Metal Scan lets you find metal up to 3 inches deep, and AC Scan lets you find live, unshielded electrical wire up to 2 inches deep BACKLIT DISPLAY lets you see the screen even when working in poor lighting conditions DIGITAL SCREEN displays bars that increase in volume as you get closer to studs or pieces of metal POINTER ARROW shines onto your working surface when directly over the object youre scanning OPTIMIZED FOR interior use only due to the uneven surfaces and varying density that comes with exterior construction techniques