Tubogas translates literally to “gas pipe” and is the descriptive name given to a type of chain formed from a pair of interlocking gold strips wrapped tightly together. This forms a flexible and hollow tubular necklace that requires no soldering. Popular during the late 1930s and 1940s, gas pipe or tubogas reflects the innovation necessitated by the scarcity of jewelry materials during World War II. Van Cleef & Arpels created a famous and versatile version of this design called Passe-Partout that could be worn as a necklace, bracelet, or belt.