Emerald Time

Emerald Time uses Network Time Protocol to display the current time of day as defined by the international standard atomic clocks. Its accuracy is limited only by network latency and is usually accurate to less than +/-100 milliseconds.
Features:
- geeky stats
- blinky lights and numbers
- display options for 12- or 24-hour, UTC or local, seconds & tenths
- NTP accuracy
- leap second display
- optional tick sounds
- optional screen brightness control
- night mode
(Requires Internet access. Emerald Time does not change the internal clock used by all other iPhone apps.)