Flange bolts have a circular edge under the head that acts like a washer to distribute loads. Standard non-serrated flange bolts are also called frame bolts. Flange bolts are used in automobiles to secure outer casings protecting engines and transmissions. In plumbing they secure pipe ends to ensure strong hold regardless of materials in the ducts. Serrated flange bolts have teeth that grip surfaces for a tight hold. In electronics flange bolts hold components together tightly to prevent particles from getting into devices. In hard-to-reach areas flange bolts help install decks and overhead attachments more easily than regular bolts and washers. Long flange bolts are used to construct oil rigs energy plants and ships.