The Clesse APZ400 & BP2203 Close Coupled 1st & 2nd Stage Regulator OPSO 75mbar is mainly used on bulk tank Domestic applications, where it provides the 1st and 2nd stage combined regulation from tank pressure to 75mbar, incorporating relief valve and OPSO. APZ400 and BP2203 are the market leading products in 1st and 2nd stage regulation, incorporating all the design features required for easy installation and after care. OPSO has easy to read visual indicator and rotating cap for pressure balancing prior to complete reset. Giro Vent on BP2203 allows multi position fitting for best protection against water penetration, and perfect drainage of humidity condensation.