Clesse APZ400 & BP2203 1st/2nd Stage Propane Tank Regulator with OPSO/UPSO – 37mbar The Clesse APZ400 & BP2203 Close-Coupled 1st & 2nd Stage Regulator with OPSO/UPSO – 37mbar is a top of the range LPG regulator system for bulk tank domestic installations. By combining first and second stage regulation in one unit it gives a smooth reduction from tank pressure to a stable 37mbar for household heating and LPG applications. With built in Over Pressure Shut Off (OPSO) and Under Pressure Shut Off (UPSO) safety systems this regulator gives you peace of mind by protecting your appliances from unsafe pressure fluctuations. Compact close-coupled design makes it space saving and easy to install and robust build means long term durability. Key Features & Benefits