This product has a voltage of 9. You get great flexibility since it runs on a battery and lacks a cord that can restrict your movements.
From ManoMano
Black + decker BDS303 Automatic 3-in-1 Stud Metal & Live Wire Detector B/DBDS303XJ
Robert Dyas
Black & Decker Black and Decker Stud, pipe & wire detector with LCD screen
This product is also available at 1 unverified merchant.