Downloading ZoneClock 3.65 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. The program lies within Productivity Tools, more precisely Timekeeping. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. The actual developer of this Mac application is Jiulong Zhao.
From the developer:
ZoneClock is a tiny but powerful world-time clock. It conveniently docks on the top system menu bar, so it's both visible and unobtrusive. ZoneClock can display times from up to four different time zones simultaneously. You can name these clocks however you wish, even with foreign and special characters.
You may want to check out more software for Mac, such as Tea Timer, Missing Sync for Sony PSP or TimeMachineGrowler, which might be related to ZoneClock.