The Contour Matrix Gas Detectors are the product of continuing research and development which BEP Marine Ltd devotes to their product range. The BEP Detectors use microprocessor control to ensure correct sensor sensitivity. The Detectors have the capability to control two sensors which detect both LPG and Petrol, with visual and audible alarms. There is a test switch to check operation of sensors with indicators for fault detection. 600-GDL Gas Detector has the same features as the 600-GD, with the additional ability to switch a valve on and off. The 600-GDL has a "pulse and hold" feature which allows the solinoid valve to to be opened, using full power, and then reducing power to hold the valve in the open position. This reduces power consumption and heat generated whilst the valve is in the on position.