Persistachron a simple transparent digital clock that floats above most windows of most applications. It displays minutes, hours, and seconds. It is small and won't get in the way. However, it can be hidden or canceled in the usual manner of applications if it is not required.
Advantages over using the menu-bar clock
Other details: Persistachron does not have an alarm. It is a simple clock. A donation window can be used to request a donation of any amount, but no lower limit. It can be dismissed at any moment. The donation key will not be displayed on any subsequent Persistachron re-launches if it is entered in the donation window. Persistachron offers a brief help book that you can access from the Help menu. It includes contact information, instructions for donations, and easy instructions. Persistachron takes up very minimal space on your hard drive (not even megabytes).