Industrial magnets are used in commercial, industrial, and office facilities to hold tools in place, locate metal studs in a wall, capture metal shavings that have fallen on the floor, and similar applications. Ceramic magnets are made from strontium carbonate and iron oxide and are used as in conveyor systems, speakers, and MRI equipment. Magnetic strips can be used to secure notices or other documents on a file cabinet, metal shelf edge, or other magnetic surface. Rare earth magnets are used in welding clamps or trailer hitch rods.