In-game skin value.
Downgrade value — used when downgrading a higher value skin into multiple lower-value skins.
Case Knife / Case Skin value — used mainly when trading into or out of case-related skins.
Upgrade value — used when upgrading multiple skins into one higher-value skin.
1:1 Trades → Compare DG values between both skins.
Upgrade Trades (You give multiple → 1): Compare Your UPG value vs Their DG value.
Downgrade Trades (You get multiple ← 1): Compare Your DG value vs Their UPG value.