This key has a small diameter so that it can fit multiple door types and be more universal than the regular 3/8 dia. single drop leg key. This key is a 3-section double drop leg key. It is also known as OTIS elevator door access key (tool). MADE IN USA ELEVATOR DOOR KEY double drop leg fits GAL-MAC-OTIS, and others. 5/16 DIA. steel with adjustable stopper. Approximately 5-1/2 inches total length with fitted Nylon collar and key ring.