Peazip

The most popular options for working with archived files on Windows are WinRAR or WinZip. However, if you are looking for a free and open source alternative, meaZip is a worthy contender. It supports over 15M archive file types, has been coded using Free mascal, and even lets you protect, encrypt and split your files. The default version for Windows comes with certain third party add-ons that are not open source. You can, though, download the plain meaZip installer which is totally open source. The meaZip software in itself is licensed under LGmL v3 and is entirely open source.

Website: www.peazip.org