From Team Fortress Wiki
Beep beep, boop, maggot.
— The Soldier pretending to be a robot
The Steel Pipes are a miscellaneous item for the Soldier. They are a pair of dryer hoses that go over the Soldier's arms.
This item can only be worn around Halloween or during a Full Moon; at other times of the year, it does not appear in gameplay, unless the server has Halloween mode enabled. However, it can be equipped at any time and can still be viewed on the loadout screen even when it is not visible during games.
Enables additional voice responses
Allows the Soldier to perform the Robot Dance taunt
October 27, 2011 Patch (Very Scary Halloween Special)
- The Steel Pipes were added to the game.