M40 Multi-Gas Monitor features peak/hold readings, 50-hour datalogging, high/low, STEL, TWA and low battery alarms. 90dB audible alarm, ultra-bright LED visual alarm and a vibrating alarm warns when dangerous levels of gas are detected. Rechargeable lithium-ion battery lasts up to 18 hours. Dimensions: 4.3"H x 2.45"W x 1.37"D, weighs: 8.6 oz. Includes a high-visibility, impact-resistant composite case, compact charger, calibration cup, tubing, belt clip, maintenance tool and instruction manual.