DIN valves are installed on cylinders with service pressures exceeding 3000 psi. These valves are designed for use with regulators equipped with DIN attachments instead of yoke attachments. The regulator is attached by screwing its DIN fitting into the valve's internal threads.

With these valves the o-ring is attached to the regulator instead of the valve. The o-ring is thicker than yoke valve o-rings, and is more dependable. This system is sometimes referred to as a "captured o-ring."