The Chroma Case is a weapon case added to the game in 2015 that contains 14 weapon skins, ranging from Mil-Spec Grade to Covert, with knives as its rare special item. SkinsMonkey lists every Chroma Case skin with prices for each wear level.
The chroma case was added to the game in the January 8th 2015 update. In the update there were 14 community-designed weapon skins added, which can be opened in this container. Players who open the chroma case also have a chance to get a special rare knife skin, each with one of the twelve possible finishes.
To open the chroma case, you need to first get the chroma case key. You can buy it in the in-game store, or trade for it with other players.
When you open the chroma case, you have a chance to receive one of the following weapon skins:
The 14 weapon skins from this container make up The Chroma Collection, the set that counts in trade-up contracts. The knives it drops as rare special items belong to no collection.