Use the "300 bar" DIN to convert your first stage from a yoke valve to a DIN valve. This is a necessary piece of equipment for any divers who want to switch between many aluminum and steel tanks. Also, scuba divers who travel overseas will want to have a DIN adapter in order to adapt to the tanks available at the local dive sites. The adapter allows you to easily convert your first stage, if required, so you can use your own gear rather than rental gear!