Timer.NET

Developed in C#, Timer.NET is an easy-to-tool that facilitates a basic countdown timer and stopwatch. It doesn't contain any complex features, geared toward all types of users looking to rapidly count time for various purposes, such as cooking, studying, or taking a break from work.

No setup required, besides .NET Framework

The whole program's wrapped in a single .exe file that you can copy to a preferred location on the hard disk or to a USB flash drive, in order to directly launch it on any computer.
It doesn't add new entries to the system registry or modify existing ones, nor does it create new files on the HDD. However, it depends on .NET Framework, since it was developed with the aid of this platform.

Start and pause a countdown timer or stopwatch

When it comes to the interface, Timer.NET opts for a standard .NET Framework form and doesn't put emphasis on visual appeal, preferring to focus on functionality instead. It's split into three panes, for the timer, stopwatch and a to-do list, and it also includes a menu bar.
You can enter time in hh:mm:ss format to count it down from, as well as pause or stop it, along with the stopwatch. Milliseconds aren't supported. The todo list has yet to be implemented into the application, so it exists purely for preview purposes at the moment. There are no other notable options provided by this piece of kit. It doesn't contain any kind of customization properties.

Evaluation and conclusion

Unsurprisingly from such a compact utility, Timer.NET had minimal impact on the overall performance of the computer, running on a low amount of system resources. It remained stable throughout its runtime, without hanging, crashing or prompting errors. We haven't experienced any compatibility issues with the latest version of Windows.
Nevertheless, Timer.NET is a rudimentary time-tracking tool, wrapped up in a plain interface and featuring only the necessary and suffice options for using a countdown timer and stopwatch.