Click on the file named zmule-2.1.8-win32-setup.exe. The download size is approximately 4.8 MB. Do not download any "enhanced" or "pro" versions — they are fake.

While ZMule 2.1.8 is a legal tool, what you download with it may not be. Always respect copyright laws in your jurisdiction. The eD2k network is also used for legitimate purposes:

We encourage using ZMule to share and download only legal content.

A common concern is whether using an older version like 2.1.8 is safe. The short answer: yes, with caveats.