Patent-pending CenterVision technology finds the stud center in 1-step. Finds the center and edges of studs and joists, finds copper pipes (and other nonferrous metal) up to 1-1/2" (38mm) deep, finds rebar (ferrous metal) in concrete up to 3" (76mm) deep, and detects and traces hot AC wires. Exclusive, patented SpotLite Pointing System shines a bright beam of light over target center.