Refreshing Summer Cooler Key
From TF2 Wiki
The Refreshing summer cooler key is a misc. item found in the Mann co. store. It was added to the game on the 1st of July 2011. It is used to open the Refreshing summer cooler(crate series #22). The contents of the cooler is unknown for now. It can be bought for 1.99 euro's. It says on the description that the key will expire on the 11th of July 2011, and then become a normal Mann co. key.