What underwater breathing device did Leonardo da Vinci sketch for divers?

Leonardo da Vinci sketched a diving suit intended to let a diver breathe underwater.

His notes and drawings describe a full-body suit connected to the surface by breathing tubes. The design included a mask, a hood, and a system for supplying air. Leonardo developed the idea while studying military possibilities for underwater operations, including covert attacks on enemy ships.

The sketch is often called an early diving suit, but it was not a modern self-contained scuba system. The diver remained connected to the surface, and the practical performance of the proposed equipment is uncertain. Leonardo’s work is important because it shows a systematic attempt to solve underwater breathing, buoyancy, and movement problems long before reliable diving technology existed.