A padlock type seal is a type of plastic seal that is used as an advantageous and secure alternative to conventional padlocks. A unique, individual number is printed on each item. This ensures that the seal you have fitted has not been removed and/or replaced with another. They are most commonly used to prevent unauthorized access to objects - such as catering trolleys, boxes and even rooms. Airlines and airports are among the most frequent users of this type of fixed-length plastic seal.