Epsilon

Epsilon is a Planet in the Faction Wars Update of SAS4. It is a lush vegetative ringed planet (based on looks) filled with caves occupied by Morlok, and the only source for Epsilon Favours. Zombies living on Epsilon are reported to be healthier than usual, having an additional 10% Speed and 15% Health.

Faction Warfare Items
You can buy the following Faction Warfare items with Epsilon Favours:

Festungsbrecher

Exterminator

Mastodon Helm

Mastodon Chest

Mastodon Gauntlets

Mastodon Legs

Mastodon Boots

Trivia

 * The fact that the Mastodon Series is only buyable with Epsilon Favours is because the Mastodon Set is built for mining, and Epsilon is a lush vegetative Planet, so miners living on Epsilon may have used it for their exploration.
 * Planet Epsilon is named after Greek letter Epsilon (Ε/ε/ϵ) . In agronomy, ε is used to represent the "photosynthetic efficiency" of a particular plant or crop. This likely inspired the feature of the Planet.