Win-GZ

Win-GZ is a lightweight compression tool that can work with .gz files, providing a basic interface to handle the task.
In fact, it's not only the interface that's very limited, but the entire list of features, so you can't perform too many operations with the created archives.
Once you launch the program, you shall meet a very simple window with dedicated options to create a .gz file and keep original, delete it or name the resulted archive as original. There are dedicated options to create or extract archives, and the feature list basically ends here.
While there's no help file included in the package, which means you don't receive assistance if you need more information on a specific feature, the application doesn't even provide file associations, so you can't open .gz files on the go. Instead, you need to manually open the program every time and use the “Select File” option in the main window.
Another setback of the app is the complete lack of options regarding the compression process, so the whole task is rather simple for both beginners and those more experienced.
On the other hand, Win-GZ works flawlessly on all Windows versions and is fully portable, which means you can always copy all its files on a removable drive and use it wherever you go as a portable compression tool.
All things considered, Win-GZ is an interesting piece of software, serving its purpose with minimum effort, while providing only a limited amount of options. You can't customize the compression job, but instead you can use it on the go.