All Kestrels feature a patented user-replaceable impeller assembly.

• User replaceable
• High precision axle and low-friction Zytel® bearings
• Light weight impeller
• 25mm (1") diameter
• Factory calibrated
• Fits all Kestrel models
• Quick and easy to replace - no tools required

The impeller assembly is sold as a replacement impeller for all models in the Kestrel hand-held instrument range. It can also be used in other flow measurement applications.

The light weight impeller is mounted on a precision axle with low-friction Zytel® bearings to provide accurate flow measurements even at low wind speeds. A magnet is mounted on the axle so the impeller's rotation can be easily sensed.

The impeller housing is designed so no adjustment of the bearings is required and during manufacture each assembly is individually tested in a wind tunnel. This ensures that when a new impeller assembly is installed in a Kestrel instrument the accuracy of the instrument is restored to within specification.

The assembly is supplied with a retaining o-ring.

For customers requiring independent calibration certificates for their Kestrel, a new impeller would require re-calibration - please refer to our calibration services.