CS2 Skin Terms: A Plain Glossary

By the DuckSkins Team · Updated September 2026

Every term you will run into around CS2 skins, in one place, defined in a sentence or two. Split into three groups: what Valve calls things, what the market calls things, and what we call things on DuckSkins — because the third group is where sites tend to invent their own words for the same mechanic.

Valve's Terms

Case

A container that holds a fixed set of skins. Free to own, costs a key to open in the official client. Also called a loot box.

Key

The $2.49 item Valve sells to open a case in-game. Since 2019 keys bought in-game cannot be traded or sold, which is why in-game case opening has no resale side.

Collection

The named set a skin belongs to, such as The Bravo Collection. Collections decide what a Trade Up Contract can produce, so they matter well beyond flavour.

Rarity tier

The colour band: Consumer, Industrial, Mil-Spec, Restricted, Classified, Covert, and Rare Special for knives and gloves. The CS2 case opening guide lists the commonly cited chance for each.

Float value

A number from 0 to 1 describing wear. Lower is cleaner. It is fixed the moment the skin is created and never changes.

Wear tier

The five named bands the float falls into: Factory New, Minimal Wear, Field-Tested, Well-Worn, Battle-Scarred. Two skins in the same band can still have very different floats.

StatTrak™

A variant that counts your kills with the weapon. It is decided at creation, cannot be added later, and resets to zero if the skin passes through a Trade Up Contract.

Souvenir

A tournament-drop variant carrying player and event stickers. Souvenirs cannot be used in a Trade Up Contract.

Pattern index

A separate hidden number deciding how the texture is laid out. It is why two identical Case Hardened skins at the same float can be worth wildly different amounts.

Trade hold

Valve's delay on a trade. Without Steam Guard Mobile Authenticator active for 7 days, incoming trades are held up to a week. See Steam trade URL.

Trade offer URL

The address someone sends you a trade at — not your profile link. It carries a partner id and a token.

Market Terms

Market hash name

The exact full name of a skin including its wear, like AK-47 | Redline (Field-Tested). It is the identifier every market and every price API keys on.

Steam Community Market

Valve's own marketplace. Funds from it stay in your Steam Wallet and cannot be withdrawn to a bank, which is the whole reason third-party skin markets exist.

Buff / third-party market

Marketplaces outside Steam. Prices there are usually lower than Steam's because the money is not trapped in a wallet.

★ (star)

Prefixes knives and gloves. Anything with a star sits in the Rare Special tier and is outside the Trade Up Contract system.

DuckSkins Terms

These are ours, and we use one word for one thing. If you see a different word for any of them on another site, it is likely the same mechanic renamed.

Drop chance

The listed chance of a given skin coming out of a given case. Shown on every case page, before you open, without signing in.

Case Battle

Two to four players open the same line-up of cases at once and one winner takes the whole prize pool. Four modes — Normal, Crazy, Terminal, Crazy Terminal — and empty slots can be filled with bots.

Prize pool

Every skin every player unboxed in a Case Battle. The winner takes all of it.

Rakeback

1% of the battle cost, returned to human players who lose a Case Battle. Bots get nothing.

Contract

3 to 10 skins in, one skin out, worth between 75% and 125% of their combined value. It is a reroll, not a guaranteed step up — and it is not Valve's Trade Up Contract, which is a different mechanic with the same name.

Daily Free Case

One a day per unlocked tier, costing no balance. Tiers unlock on account level and recent deposit activity — see are free CS2 cases really free?

Instant sell

Selling a skin back to DuckSkins for balance. A different action from withdrawing, and the two are not interchangeable.

Withdraw

Sending a skin out to your Steam inventory. See how to withdraw CS2 skins to Steam.

Provably fair

The commit-and-reveal system behind every roll: a server seed committed in advance, your own client seed, and a nonce. You can recompute any past result yourself.

Server seed / client seed / nonce

The three inputs to a roll. The server seed is secret until revealed but its hash is published first; the client seed is yours and you can change it; the nonce is a counter that makes each roll in a chain distinct.

DuckSpin

The reveal animation that fires when an open lands on something unusual for that case. It changes nothing about the result or the chances.