Here's what other sites are saying:
The RH (calibrate humidity sensor) calibration kit includes the following items: * three clear, sealable containers * one container with magnesium chloride solution * one container with sodium chloride solution * two wooden scrapers * an insulated carrying case to hold all of the above and maintain a stable environment while performing calibration * For use with: Kestrel 4500, Kestrel 4200, Kestrel 4100, Kestrel 4000, Kestrel 3500, and Kestrel 3000
- Mountains Plus
The Kestrel should be recalibrated if the Relative Humidity (RH) sensor has been replaced or has shown drift in its RH measurement. The manual explains the steps for calibrating the humidity measurement. Everything needed is included.
- Vargo Outdoors