scope for user error These Compact, self contained and intrinsically safe designed instrument housed in a weather proof high impact plastic case are powered with a replaceable 4X1.2V Dc battery. On switching 'ON', the instrument goes thorough its complete self integrity check, and displays factory set Warn and Alarm values before indicating 'Ready' for monitoring While in Operation, the instrument monitors the work place continuously giving the latest update concentration of designated Gas through diffusion sampling. Suction sampling is possible with an optional manual or battery operated pump and adaptor. The poison resistant Pellister or long life, integrally mounted electrochemical Sensors with inbuilt cross interference filters are gas specific. Optionally the sensors can be mounted on an extension cable for monitoring inaccessible locations before entry. The instruments emits an audible beep every 15 sees that provides confidence to the user that he is well protected. Audio, Visual also Warn and Alarms protect him from hazardous situations.