Chaney Instruments Executive Alarm Clock

We purchased this clock expressly for our motor home travels. The criteria was to have a clock that is small, can be read in the dark, has numbers large enough to see without aid of glasses, and, most importantly, has a battery back up that will return to the correct time after an extended period without shore power. We have tested the clock at home and found it does not return to the correct time. In fact, it is at least 20 minutes fast each time we plug it in after an extended time without power. So we are very disappointed in this purchase.