On December 5, 1955, the
link U.S. Bureau of Ships created "Contract Specification; Wrist watch, Submersible, MIL-SHIPS-W-2181" to meet an operational need of Explosive Ordnance Divers
link (EOD) and Underwater Demolition Team (UDT) divers. The spec stated that the desired watch had to be watertight, impervious to water ingress, offer visibility in the
link dark, and have an outer, rotatable ring (bezel).