Boveda Small Calibration Kit 75.5% RHInaccurate hygrometer readings put premium cigars at risk. Your cigars will smoke perfectly when you store them in a steady environment between 60 and 72% relative humidity (RH). So whats the RH in your humidor? Use this 75% RH Calibration Kit to: Get an accurate RH reading in just 24 hours Calibrate a new humidity sensor, digital hygrometer or analog hygrometereven if it claims to be pre calibrated, it will be inaccurate Re calibrate each hygrometer