The infamous EM drive.
- 100 Newtons of thrust (1000x what the real thing has!)
- Heavy electric energy usage
- Running rather hot
- 300kg
- Infinite delta-V
The drive uses no fuel, just electricity, but the EM radiation does wear its structure over time, ejecting atoms of its shell into space. This is represented by 1 unit of solid propellant - which should last it a good few years; if you treat the lost mass as reaction mass, the drive has Specific Impulse of 10 million seconds. Also, the drive is entirely unaffected by atmospheric pressure.
The EM drive model is just a "brass&copper" recolor of the Ion drive; it also appears in the same research node. It's a little pricier, a little heavier than the Ion drive. It uses considerably more electricity, and requires cooling. And the thrust will really require you to leave the game running over night, or maybe over weekend... But hey, infinite delta-V!