Emerald Time is a free iOS application developed by Emerald Sequoia LLC that displays the current time using the Network Time Protocol (NTP) and is accurate up to +/-100 milliseconds. This app is designed to provide the user with a highly accurate time display that is based on international standard atomic clocks.

The app is packed with features such as geeky stats, blinky lights and numbers, and display options for 12- or 24-hour, UTC or local, seconds and tenths. Additionally, it has NTP accuracy, leap second display, optional tick sounds, optional screen brightness control, and night mode. However, it is important to note that this app requires internet access and does not change the internal clock used by all other iPhone apps.

Overall, Emerald Time is a great utility app that provides accurate time display and various customization options.