The stability of the internal master clock of both these units is as follows:
Over temperature range +/- 1 x 10-8
Over one day (24 hours warm up) +/- 5 x 10-10
Over one year continuous +/- 1 x 10-7
With the temperature range being +10 to +40 deg C (50 to 104 deg F) with the relative humidity being 40 to 90% and non-condensing.