Here's some data that may be interesting concerning the accuracy of this clock thus far. Clock with NIST, with the following results: Clock Watch NIST Watch 8:00:00 8:00:00.00 8:10:00 8:09:59.38 8:01:00 8:00:59.89 8:11:00 8:10:59.42 8:02:00 8:01:59.99 8:12:00 8:11:59.39 8:03:00 8:03:00:00 8:13:00 8:12:59.24 8:04:00 8:03:59.90 8:14:00 8:13:59.39 Average of five measurements: 8:00:00 7:59:59.956 8:00:00 7:59:59.364 So the clock is now ahead of NIST by 0.956 - 0.364 = 0.592 seconds. We started the clock speed test on 02/17/22 so now the results so far are: 03/04/22 02/17/22 Clock Time 07:59.59.956 12:00:00.176 NIST Time 07:59:59.364 11:59:59.774 Difference 0.592 second 0.402 second So the clock is now ahead of NIST by 0.592 seconds and it was originally ahead of NIST by 0.402 seconds, so it has actually gained only 0.592 - 0.402 = 0.190 seconds in 03/04/22 - 02/17/22 = 14.83333 days. So the clock is running fast by 0.190/14.8333 = 0.0128 sec/day = 12.8 ms/day = 0.39 sec/month = 4.68 sec/year. Your accuracy may vary due to climate conditions in your location, and time of year. We expect to do another calibration in a few months.