The built-in ceramic magnetics will stick to any ferrous metal surface including tool boxes, filing cabinets, grills, and equipment racks. Integrated ceramic magnets are covered by a scratch preventing rubber coating but are still powerful enough to hold up to 8 pounds. The over-large 3-5/8" inside diameter holder can accommodate most larger insulated mugs, glasses, water bottles, spray paint or lubricant cans, pens, pencils and even small tools. Made of durable impact resistant plastic. Cup holder measures 3-5/8" diameter, 3-5/8" high in the front and 4-5/8" tall in the back.