Classified is the fifth of the six weapon skin rarity tiers in CS2. It sits above Restricted and below Covert. The label is pink, so traders call these skins "pinks". The Counter-Strike wiki lists the full grade ladder and colours.
The odds that Valve's Chinese publisher Perfect World published in 2017 put Classified at 3.20% per case opening. That is roughly one in thirty cases. Because a case key costs money and most openings return a blue or purple, a pink is usually the first result that feels like a win, though it often still returns less than the key cost.
Why do Classified prices vary so much?
A pink on a popular gun with a clean design can outsell a red. A pink on a weapon nobody plays can sit at a few dollars. Wear tier and float matter more at this level, because buyers who spend real money on a skin often want a Factory New or Minimal Wear copy. StatTrak versions cost more, and skins from cases that left the drop pool tend to climb over time as supply stops growing.
Can Classified skins be traded up?
Yes. Steam Support's trade-up rules say ten skins of one rarity return one skin of the next rarity from one of the input collections, so ten Classified skins return one Covert. This is the most expensive kind of weapon trade-up, since ten pinks can cost a lot, and the Covert output might be worth less than the inputs. Traders check the collections carefully, because a case with one expensive red and one cheap red gives a coin flip with very different payouts.
Classified skins are also the output of a Restricted trade-up, so they sit in the middle of the trade-up ladder as both a target and an input.