Magnet Magnetic Sign - Property Inspector Caution Frequent Stops For Vehicle, Car Or Truck - 3 x 14 inch Magnetic sign made from .030 thickness magnetic sheeting, not the thinner inexpensive promotional magnet. Will hold well on any flat clean smooth metal surface Use care when applying or removing. Remove magnets at least weekly and clean the application surface and back of magnet. We send along a magnetic sign care/tips sheet.