In November 2008, CCP introduced PLEX, the CONCORD Pilots License EXtension, which is an in-game item that can be used to extend a subscription for 30 days. PLEX can be purchased on the Eve Online website for real money, or inside the game for ISK. 60-day ETCs can be converted to two 30-day PLEX within the Eve Online client, which can then be sold via the in-game market. PLEX is the reason that the cost of in-game assets can be translated into real-life money. As the price of a PLEX is around €15, it can be calculated how much a certain ship or implant is theoretically worth in a real currency.