ToxiPro polycarbonate hydrogen cyanide, single-gas detector. 0 to 100PPM measuring range. is a handheld single-gas detector that uses an electrochemical cell sensor to measure hydrogen cyanide (HCN) continuously and that has audio and visual alarms which alert simultaneously when HCN reaches any of four preset levels. The detector has a backlit alphanumeric LCD screen that can be adjusted by the user to show the current gas level the maximum gas level recorded during the current operating session the battery level and the time. The LCD display also features a blinking heartbeat icon to indicate normal functioning. It is operated and adjusted with a single push button. This detector is used to indicate potentially harmful levels of HCN gas naturally occurring in the environment in a variety of occupational settings such as petroleum refineries tanneries sewage treatment facilities and paper mills and in other personal safety educational and ambient monitoring applications.