The Arc Reactor was introduced on August 3, 2012 as the twenty-forth non-cash generating property in New York / Manhattan. This is a limited-time-to-upgrade property in which you have 16 days to upgrade to level 15 (or as far as you can). After this period you will no longer be able to upgrade normally. You get to keep the level you reached and are able to build the items. However, you can still buy the required upgrade parts using Reward Points. Unlike regular crafting properties, there is no cost-per-item each time you craft.