FEX two stage self-driven pressure regulators are widely used both in civil and industrial installations using Natural gas, LPG or not corrosive gases. They are designed for direct installation to a gas meter or use in general pipeline work. They can be installed in any position provided that they are protected against atmospheric agents. The internal relief valve vent can be convoyed outside in case of installation with closed rooms or for underground plants. Thanks to the concept of double regulation stage, it is possible to achieve a high accuracy and high operating reliability. Simple installation procedure. The regulator are manufactured according to UNI 8827.