: Persian divers used polished tortoiseshell to create diving goggles.

: Developed in 1941, this military helmet was deeper and more rounded than previous models to provide better protection.

: Its resemblance to a turtle shell was so strong that the nickname "turtle helmet" became standard among soldiers. 3. Modern Lightweight Helmets (1960s – Present) Modern Evolution of Diving Equipment

: These helmets were often referred to as "copper hats" and were designed to withstand immense pressure for salvage and underwater construction. 2. The "Turtle" Helmet Nickname (1940s)