WHEN IT COMES TO SCUBA GEAR, DID YOU KNOW?

1. Round dive masks without a nose pocket required a diver to block the nostrils with the rubber skirt to equalize.

2. The original Aqua Lung was developed for World War II underwater demolition by Jacques-Yves Cousteau and Emile Gagnan. It was first sold as scuba gear in the U.S. in 1952.

3. Early double-hose regulators required a diver to carry more weight to compensate for the bouyancy of the two hoses.

4. The terms “J” and “K” valve refer not to shape or function, but instead to codes in 1950s AquaLung (US Divers) catalogs. The “J” was the constant reserve valve and “K” was the nonreserve valve.

5. There were no pressure gauges: The J valve functioned with a mechanical valve that stopped airflow at 500 psi. When alerted to low gas supply, the diver would pull a lever to open the valve and surface using the remaining air.

6. Exhaled air was vented behind the diver’s head with double-hose regulators, which employed an air-delivery hose and an exhaust hose. With no bubbles in a diver’s face, this primiive scuba gear was great for photography and less intrusive to marine life.

7. The first wetsuits were “quarter-inch” in thickness, and featured high-waisted pants and a jacket with a beavertail flap that joined to the jacket through the legs.