AM2_1.1.1b.zip is a release file of the Minecraft mod Ars Magica 2, made for Minecraft 1.6.4. It was published on December 31, 2013 and is 18.6 MB in size. For the full description, screenshots and every other version, visit the Ars Magica 2 mod page.
How to install: Put the .jar into the mods folder (.minecraft/mods) and start Minecraft with the matching mod loader profile.
