Ambient Weather RHCOMBOCAL-KIT Two-Point 33% and 75% RH Humidity Field Calibration Kit for Weather Station Hygrometers

This kit features 33% and 75% RH Humidity packets that maintain 33% and 75% RH by releasing and absorbing water vapor as needed through the membrane and a reclosable 4" x 8" reclosable bag (for each) multiple uses.