The listing, Chemistry Set of EIN Team Fortress 2 ( TF2 ) STEAM has ended.
Chemistry Sets are recipe items that have varying inputs and varying outputs. A Chemistry Set can be completed by fulfilling all of its inputs, which will then give the items it has listed in its outputs. There is an indicator in the upper left corner of the Set's inventory icon indicating the number of inputs possessed. Chemistry Sets can reward a Strangifier for the item the set is associated with, which, when used with the item, will turn it into a Strange variant; or a Collector's quality version of the same item.