Calculated Industries 8119 Plug Mark Drywall Electrical Socket Locator Accessory Accessory item for rehabilitation and drywall replacement installations (requires use of #8105 Blind Mark Locator magnet, not included) Perfect drywall cutouts in half the time with NO measuring using powerful rare-earth magnets Get professional results you can be proud of your first and every time with foolproof patented technology Pays for itself by avoiding costly and embarrassing measuring errors Two included Targets fit any standard 3-prong plug outlets for any rehab or drywall replacement installations