Direct Operated Tank Padding Regulator or Gas Pressure Reducing Regulator for Low Pressures 1-1/2" - 2" (DN40 - DN50) The Mark 608 gas pressure regulator is used on large tank blanketing applications or other low pressure gas regulation. In a tank blanketing application, the Mark 608 is used to control the flow of the blanketing gas into the tank to maintain the proper positive pressure. Once the blanket has been established, a small flow of nitrogen is continually admitted to the tank to keep the blanket fresh.