The Spectrum Case is a weapon case released in 2017 that holds 17 weapon skins, from Mil-Spec Grade to Covert, with knives as its rare special item. SkinsMonkey lists every Spectrum Case skin with prices for each wear level.
The Spectrum case was introduced as a part of an update released on 15th of March 2017. The weapon case contains 17 community-designed skins, with a chance to open special super rare quality knife finishes.
The 17 skins that you can open in the spectrum case include: 2 covert, 3 classified, 5 restricted and 7 mil-spec rarity weapon skins.
To open this case you will need to have a spectrum case key in your steam inventory. When opening the spectrum case you can get the following skins:
The 17 weapon skins from this container make up The Spectrum Collection, the set that counts in trade-up contracts. The knives it drops as rare special items belong to no collection.