With a comprehensive range of features and functions, GasAlertMicro has set a new benchmark in multi-gas detection. At just 7.3 oz. (211 g), the rugged GasAlertMicro is unrivalled in performance and value-added affordability. Simultaneously displaying O2, H2S, CO and combustibles present, GasAlertMicro is ideally suited to a wide range of applications. Choose a 4, 3, or 2-gas model in safety yellow or black, with optional datalogging. Comes standard with 2-AA batteries. Other power options are available in lieu of alkaline abtteries. Features High-contrast LCD shows continuous and simultaneous real-time gas concentrations LOW, HIGH, TWA (time weighted average) and STEL (short-term exposure limit) alarms High-output 95 dB audible alarm Dual visual alarm bars Internal vibrator alarm (standard) Built-in concussion-proof boot Backlight in low light (auto), in alarm (auto) and on demand Simple auto zero and auto calibration with diagnostics protection Records and displays TWA, STEL and peak exposures to gas on demand Continuous instrument status advice Flexible power source--disposable AA alkaline (16-18 hours) standard or rechargeable NiMH (14-16 hours) Accessories Manual aspirator pump Confined space kits Self-Tests Full function self-test verifies sensor, circuitry battery, integrity and audible/visual alarms Continuous battery test and instrument status diagnostics