Production information
Manufacturer Coventry/Earthwerks Combine
Production Year 2790[1]
Model FFL-4B
Class Light
Cost 2,342,600 C-bills
Technical specifications
Mech type Inner Sphere BattleMech
Mass 30 tons
Chassis Earthwerks Firefly
Armor StarSlab/1
Engine GM 150
Communications System Datacom 18
Targeting Tracking System Radcom TXX
Heat Sinks 10
Speed 86.4 km/h
Jump Jets Lexington Lifters
BV (1.0) 716
BV (2.0) 870[2]


Until the arrival of Wolf's Dragoons in 3005, the 2790 Firefly was a 'Mech thought to be extinct from the rigors of the Succession Wars. The Firefly is a well-armed recon 'Mech that tips the scales at thirty tons. Since it was reintroduced to the Inner Sphere, the 'Mech has been refitted by the Wolf's Dragoons with Star League technology. It has a maximum ground speed of 86.4 km/h and can jump up to one hundred and twenty meters. As a scout 'Mech, the Firefly gives average performance with its energy weapon-heavy arsenal and is useful in both a recon and in a guerrilla fighter role.

Weapons and Equipment[edit]

The Firefly is armed with a Coventry Five-Tube LRM-5 for long-range firepower and to attempt to keep enemies at a distance. If facing a determined enemy that is intent on closing, the Firefly carries three Martell Medium Lasers, which can cause a considerable amount of damage. Finally, to protect against missile attacks, the Firefly carries a SureFire 444 Anti-Missile System in the left arm, with a "false" AMS in the right arm.[3]


  • FFL-3PP 
    A Pentagon Powers variant of the FFL-3SLE that removes the CASE and ECM in order to upgrade the missile rack to an LRM-10. BV (2.0) = 888[8]
  • FFL-3PP2 
    Another refit of the FFL-3SLE, this time simply using standard armor plating instead of the advanced Ferro-Fibrous composites. BV (2.0) = 873[9]
  • FFL-3PP3 
    Again lacking in Ferro-Fibrous armor, this variation on the -3SLE also removes the ECM system, instead upgrading the LRM rack with an Artemis IV fire-control system. BV (2.0) = 808[10]
  • FFL-4A 
    An early variant of the Firefly, and one that accompanied the Dragoons to the Inner Sphere, the 4A carries a similar weapons payload to the 4B model, although it keeps the small laser battery of the -3A instead of the anti-missile system. BV (1.0) = 649, BV (2.0) = 831[11]
  • FFL-4D 
    A comparatively new variant that appeared with the Dragoons shortly before the fighting on Outreach, the 4D saves weight through the use of a Light Engine, Endo Steel, and Ferro-Fibrous armor. Like the 4C, this variant adds an Artemis IV FCS to the LRM-5. The D, however, upgrades the lasers to ER Medium Lasers. Due to space constraints, the 4D uses twelve single heat sinks that are sorely taxed. BV (1.0) = ??, BV (2.0) = 894[13]
  • FFL-4DA 
    An electronic warfare variant of the FFL-4D model, the 4DA replaces the Anti-Missile System and its ammo with a Guardian ECM Suite. BV (2.0) = 921 [14]


  • In German products the unit's proper name was altered to Zecke, which rather means Tick. The model code was accordingly changed to ZCK-4A.



  1. MUL online date for the Firefly
  2. Technical Readout: 3050 Upgrade, p. 17
  3. Technical Readout: Succession Wars, p. 20
  4. Historical: Operation Klondike, p. 165
  5. Record Sheets: Succession Wars, p. 28
  6. MUL online entry for the FFL-3A variant
  7. Record Sheets: Operation Klondike, p. 28
  8. Record Sheets: Operation Klondike, p. 29
  9. Record Sheets: Operation Klondike, p. 30
  10. Record Sheets: Operation Klondike, p. 31
  11. Record Sheets: Operation Klondike, p. 32
  12. Master Unit List: Battle Values, p. 94
  13. Master Unit List: Battle Values, p. 95
  14. Starterbook: Wolf and Blake, pp. 29, 95.
  15. Record Sheets: Upgrades, p. 41
  16. Record Sheets: Operation Klondike, p. 33