StatTrak™ Weapons can only be found by opening Weapon Cases. They can apply to any gun skins or knife skins. StatTrak™ variants are not available for vanilla weapons, but are available for vanilla knives, excluding the default knife.
StatTrak™ guns have an orange LED number display attached to the gun to track the number of kills, while StatTrak™ knives have the confirmed kills etched into the blade. Kill counts exclude all bot kills, regardless of the bot's skill level.