Lead is used for shielding in x-ray machines, nuclear power plants, labs, medical facilities, military equipment, and other places where radiation may be encountered. There is great variety in the types of shielding available both to protect people and to shield equipment and experiments. In gamma-spectroscopy for example, lead castles are constructed to shield the probe from environmental radiation. Personal shielding includes lead aprons (such as the familiar garment used during dental x-rays), thyroid shields, and lead gloves. There are also a variety of shielding devices available for laboratory equipment, including lead castles, structures composed of lead bricks, and lead pigs, made of solid lead or lead-lined containers for storing and transporting radioactive samples. In many facilities where radiation is produced, regulations require construction with lead-lined plywood or drywall to protect adjoining rooms from scatter radiation.