What is there to say, it's a stop watch, measuring up to 100 hours, showing hours, minutes and seconds. The display wraps after 100 hours. A lap feature is also included.
This software is provided as FREEWARE, and will run on any version of Windows. No install is necessary to run Stop Watch, just download, unzip and run.
If this application simply does what you want, with no problems, why not consider funding BTT Softwares future development, by donating a small amount via PayPal?