A universal killstreak kit is a killstreak kit that is not associated with a specific target item. This allows the kit to be applied to any item in your backpack.

Universal killstreak kits were introduced as a bug twice in TF2's history.

• Gun Mettle - Most of them come from the Gun Mettle update in 2015. After Gun Mettle launched, a bug caused all specialized and professional killstreak kit fabricators that were received as MvM loot to not be associated with any item. When the fabricator is completed, it produces a universal kit.
  
• Scream Fortress 2016 - When Scream Fortress 2016 launched, some professional killstreak kits that were unboxed were universal and notably were missing a sheen. It is not clear how long this lasted or which crates it was specific to.

The fabricators look like typical fabricators in your backpack and list the required ingredients, along with the craft result:




The resulting kits look and act like regular kits but have no item visible in their icon:





When applied to an item, it functions exactly as expected:




For professional kits that do not have a sheen, the behavior is the same, just with no sheen along the way:





In general, if a universal kit is applied to an item that is not a weapon, there should be no expectation of the killstreak count, sheen or killstreaker working. The bonk helm is a notable exception where the killstreak sheen does visibly show on the Bonk! cans on the helmet.

When applied to weapons that do not normally support killstreaks, the behavior is not consistent. Some weapons show the killstreak sheen, like gunboats, and others do not, like the razorback.

Notably, when applied to a Spellbook Magazine or Fireproof Secret Diary, it allows these items to count kills with spells towards a killstreak.

If the kit does not have a sheen, there will never be any sheen or killstreaker on any item it is applied to, even if the item normally supports a sheen. The killstreak count does still work if the weapon supports it, so kits without a sheen effectively behave like basic killstreak kits.

A sheenless/killstreakerless killstreak kit refers to a specialized killstreak kit that has no sheen, or a professional killstreak kit that has no sheen and no killstreaker. The kit can be applied to a target item and the killstreak is identified as specialized or professional, but functions like a basic killstreak.

Sheenless/killstreakerless kits were introduced twice in TF2's history.

• Gun Mettle - After the Gun Mettle update in 2015, a bug was introduced where specialized and professional killstreak kits were incorrectly allowed to be restored in game. Restoring the kit would remove the sheen and/or killstreaker.
  
• Non-public Exploit - In August 2024, a player discovered an exploit to forcefully restore kits, effectively resurrecting the Gun Mettle bug. The details of this exploit are not public.

The kits look and behave like regular kits, minus any sheen and/or killstreaker:





An interesting note is that this bug was also possible on universal killstreak kits, creating the existence of universal specialized and professional kits with no sheen or killstreaker:




A sheenless/killstreakerless kit that is applied to an item will never show any sheen or killstreaker on any item it is applied to, even if the item normally supports a sheen. The killstreak count does still work if the weapon supports it, so these kits effectively behave like basic killstreak kits.

A "Specialized Tier with Killstreaker" item is an item that is assigned a specialized killstreak tier, but also has a killstreaker applied to it.

The bug is isolated to the following items:

• Huntsman
  
• Back Scatter
  
• Minigun
  
• Ambassador
  
• Stickybomb launcher
  
• Kritzkrieg
  
• Backburner
  
• Frontier Justice
  
• Direct Hit

This is the same list of items that can have killstreak kits unboxed from Crate #84 so it is likely that the bug had something to do with kits unboxed from this crate, but the exact nature of the problem's origin is not clear.

When viewing one of these items in game or through Steam inventory, the item is displayed as professional killstreak and is indistinguishable from a true professional killstreak item:



However, community sites like backpack.tf accurately show the item's tier:



Interestingly, even though Steam labels these items as professional killstreak, community market listings for the same items are labeled as specialized killstreak:



The items behave exactly like professional killstreak items, with the sheen and killstreaker functioning as expected.