The One-Step Calibration Kit utilizes Boveda's 75% or 32% relative humidity standard. A one point calibration will only require the 75% RH standard while the two point calibration will require both the 75% RH and the 32% RH standards.
To begin the calibration, start with the 75% RH standard. Simply place your sensor inside the bag and close the zipper. Following the App's instructions, allowing the Calibration Kit to sit for a minimum of 24 hours at room temperature, 65 to 80°F. The App will tell you when the 75% RH calibration has completed. Continue following the App's instructions and if you are performing a one point calibration, you're done.
If you are performing a two point calibration, continue following the App's instructions and place the sensor in the 32% RH bag and close the zipper. At the end of the second 24 hour period, the App will again let you know when the second point has completed. Follow the few remaining steps and you're done.
A perfectly calibrated sensor will read 75% or 32% RH (depending on the calibration kit you are using). If your sensor reads above or below that number, the App will adjust the calibration value by the number of percentage points it is off from 75% or 32%, commonly called the offset.