CNG (Natural Gas) pressure regulators, electronically controlled device to reduce NG pressure, allowing homogeneous gas flowing throughout the engine rev range. Three NG regulation stages are provided enabling the device to effectively stabilise the gas pressure. To prevent freezing after sudden gas expansion, the regulator is heated by using water from the engine cooling circuit. The gas flow necessary to ensure engine idling is adjustable via a gas port separate from the main gas flow. Inclusive of an electronic starter device with a built-in safety system which operates by shutting off the gas solenoid valve at every (wanted or unwanted) engine stop. The regulators are equipped with a clever (patented) compensation device allowing the regulator to be installed at any position including transversally with respect to the vehicle travelling direction. All the NG regulators are homologated according to the EEC directives 10R- 00, ISO15500, 10R-02 (Electromagnetic compatibility).