This breakout board is focused around Renesas' FS3000, a surface-mount air velocity module utilizing a MEMS thermopile-based sensor. It features a digital output with 12-bit resolution and comprises a “solid” thermal isolation technology and silicon carbide coating to protect it from abrasive wear and water condensation.
It measures air flow speed up to 7.23 m/sec with an accuracy of 5 % full scale flow range. Sparkfun has written an Arduino library to help you get started quickly.
More information is available on the website of Sparkfun.