Gladhand seals fit standard gladhands to prevent air from escaping air lines that connect trucks or semi-tractors to trailers. Seals are sometimes colored blue or red to match service or emergency gladhands, while silver/black are universally used. Multiple styles, including open, closed, and partial are available. Seals may include screens, filters, or dust flaps to keep contaminants or debris from entering airline. Open and partial seals use screens.