Diving gear is beautiful in its own way (should you have a passion for fine mechanics, anyway)
The MK20 is a first stage, part of a series of equipment to provide a diver with air. Its function is to bring the pressure in the cylinder (about 200 – 300 bar) down to about 10 bar. The second stage brings the pressure down to the pressure of the surrounding water. (picture below: A R190 second stage, known as the workhorse of the Scubapro line of second stages)
