CRAFTSMAN Center Finding 0.75" Depth Stud Sensor Finder w/ AC Detection (CHMT77620) - powered by 2x AAA batteries (batteries included) - brand new in package - $20 firm FEATURES: - Detects center of stud for accurate results - Detects wood and metal studs up to 3/4-in deep - Auto calibration for consistent readings - Detects presence of live AC - Thin profile for ergonomics and storage - LED arrows and audible notifications of stud location