Dwyer A-SAH-15S is a Smart Air Hood® Balancing Instrument. It can be powered by a 3.6 V NCR18650B MH12210 lithium ion battery or 4 AA alkaline batteries. With a response time of 1 second and a resolution of 1 CFM (1.7 m³/h) (.5 l/s), it accurately measures air flow ranging from 40 to 2000 CFM (68 to 3398 m3/h) (19 to 944 l/s). It uses Wi-Fi direct low energy wireless technology and is compatible with the SMART Air Hood® application software. The instrument is made of polypropylene and supports units in CFM, m3/h, and l/s. Accuracy for airflow greater than 40 CFM is ±3% of reading ±7 CFM (11.9 m3/hr) (3.3 l/s)*.