Dr. Christian J. Lambertsen, known mostly for inventing the parts necessary to scuba dive, died yesterday at 93 years old. His revolutionary device made it possible for people to breathe while underwater. It was even used by the military in World War II. Called the “Self Contained Underwater Breathing Apparatus”, the name was eventually shortened to the acronym SCUBA, reports DenverPost.com.

His 1939 invention, the Lambert sen Amphibious Respirator Unit, or LARU, is considered a forerunner of the scuba technology used today.

Before World War II, military divers wore clunky metal helmets that pumped breathable air through hoses tethered to boats on the water’s surface.

Lambertsen’s LARU let divers swim freely and stealthily. It used pure oxygen and was a closed system. Equipped with a carbon dioxide filter, it enabled the diver to re-breathe the air he exhaled while underwater, which made the system bubbleless.

After the Navy rejected his device at first, Lambertsen demonstrated the LARU in the swimming pool of the Shoreham Hotel in Washington in 1942 to the Office of Strategic Services, the World War II predecessor of the CIA.

Not only was the OSS impressed with the invention, the nascent spy agency saw great potential in the young medical student, who was an experienced diver.

Lambertsen joined the Army Medical Corps and, later, the OSS.

Patent image from Google Patents