A Leader in Digital Avionics 40 years ago, Davtron designed and manufactured our 811 series clock for aircrafts. This 811 series clock was installed in Air Force One aircrafts SAM 26000 and SAM 27000. Davtron clocks have been installed on all Air Force One planes since 1974. With over 40,000 811 clocks in the field, the 811 series remains in production today. With this clock's long esteemed history, it will surely be a topic of conversation. Check out the 811 series enhanced Digital Clock M811C with long lasting displays and coin cell battery back-up with limited supply at reduced cost.