Used but working perfectly Advance model 4135 digital alarm clock. The red lighted numbers are 5/8 inch tall and easy to read. The control buttons allow the time and alarm change to be done by changing the hour or the minute digits individually. The clock is small enough to be used anywhere and it has a 9 volt battery for backup in case of a power outage that is in place. The clock is 5 3/4 inches long by 3 inches deep by 2 inches tall. The numbers provide enough light to be a defacto night light.