Rechargeable portable gas mass flow meters provide 18 hours of continuous operation on a single charge and +/-0.8% of reading accuracy. The hand-held meters bring laboratory-class accuracy to field flow verification and validation applications in the environmental, manufacturing and metrology industries. They provide fast flow validation with multi-parameter measurement, wide operating ranges and multiple true gas calibrations. With no moving parts and no warm-up time requirement, they are useful for field technicians who require fast and durable flow measurement. Alicat