When y'all meet your maker, tell him to build you some guts next time.
— The Engineer
The Operation Mecha Engine Badge is a cosmetic item for all classes. It is a gray disk featuring a winged wrench.
This item is awarded to players when they complete their first mission of the "Operation Mecha Engine" Tour of Duty in Mann Up mode. It tracks a player's progress through the various Mann vs. Machine missions, and its level increases based on the number of Tours completed.
December 20, 2012 Patch #1 (Mecha Update)
- [Undocumented] The Operation Mecha Engine Badge was added to the game.