This article is about the light STO-series BattleMech. For the apocryphal ultralight STD-series BattleMech, see Stiletto (StarDrive).
Production information
Manufacturer Coventry Metal Works[1]
Production Year 3061[2]
Model STO-4A[1]
Class Light
Cost 5,167,125 C-bills[2]
Technical specifications
'Mech type Inner Sphere BattleMech
Mass 35 tons
Chassis MatherTech 750 [endo steel]
Armor Lexington Ltd. High Grade Ferro-Fibrous with CASE
Engine VOX 280 Light Engine
Communications System Cyclops 14 with Guardian ECM suite
Targeting Tracking System Cyclops-Beagle
Heat Sinks 10 double
Speed 129 km/h
BV (1.0) 746[3]
BV (2.0) 859[1][2][4]


The Stiletto was engineered in a similar vein as the Black Hawk-KU or the Rakshasa, using examples of Fire Falcon OmniMechs salvaged from the battlefield immediately following the Battle of Coventry. Not only does the Stiletto have an identical speed profile as the Fire Falcon, thanks to a VOX 280 light engine giving it a top speed of 129.6 km/h, but it also has an almost identical visual profile to the 'Mech which it tries to emulate. Supporting this is a lightweight MatherTech 750 endo steel chassis that supports six tons of Lexington Ltd. High Grade ferro-fibrous with CASE to protect against an ammunition explosion.[5]

Weapons and Equipment[edit]

The Stiletto is armed for both long and short range combat. For close combat, the Stiletto has two Coventry T4H Streak SRM-2 launchers while long range combat is handled by a single Coventry Five-Tube LRM-5 launcher that makes the Stiletto capable of both direct and indirect missile support. The weapons payload of the Stiletto has received some criticism, as the 'Mech carries only one ton of LRM and Streak ammunition, rendering it defenseless once these are depleted. The Stiletto also has a Guardian ECM suite which protects the 'Mech from advanced electronic warfare equipment.[5]


  • STO-4B 
    Designed in 3063[6] as a response to criticism over the 4A variant's ammunition dependence, the 4B removes all of the missile weapons and CASE and replaces them with a single ER large laser and two ER medium lasers. A flamer rounds out the arsenal on the 4B, making the 'Mech highly effective against unarmored infantry.[1] BV (1.0) = 936[3] BV (2.0) = 1,164[7][6]
  • STO-4C 
    This variant, developed in 3076[8], replaces the standard weaponry with a pair of ER medium lasers and an MML-5. It also adds additional armor to round out its tonnage. BV (2.0) = 941[9][8]

Apocryphal Content Starts

The information after this notice comes from apocryphal sources; the canonicity of such information is uncertain.
Please view the reference page for information regarding their canonicity.

  • FRF-J 
    The FRF-J has the same armament as the FRF-A and six tons of armor. Its jump jets allow it to jump up to 134 meters.

Apocryphal Content Ends

Design Quirks[edit]

The STO-4A Stiletto has the following Design Quirks:[14]

The STO-6S Stiletto has the following Design Quirks:[12]

Related BattleMechs[edit]

  • Fire Falcon - The 'Mech was conceived from captured Fire Falcon OmniMechs.


  • The Stiletto appears in FASA Interactive's expansion pack for MechCommander, Desperate Measures. Desperate Measures was released in 1999, three years before the Stiletto's canon appearance in Technical Readout: 3067.
  • In German products, the unit's proper name was translated to Stilett. The model code was accordingly changed to STL-4A.



  1. 1.0 1.1 1.2 1.3 Technical Readout: Jihad, pp. 62–63: "STO-4A Stiletto"
  2. 2.0 2.1 2.2 MUL online entry for the Stiletto
  3. 3.0 3.1 Combat Operations, p. 132: "Force Faction Tables"
  4. Record Sheets: 3067 Unabridged, p. 85
  5. 5.0 5.1 Technical Readout: 3067, pp. 56–57: "STO-4A Stiletto"
  6. 6.0 6.1 MUL online entry for the Stiletto STO-4B variant
  7. Record Sheets: 3067 Unabridged, p. 86
  8. 8.0 8.1 MUL online entry for the Stiletto STO-4C variant
  9. Record Sheets: 3067 Unabridged, p. 87
  10. Experimental Technical Readout: Steiner, p. 3: "STO-6X Stiletto"
  11. MUL online entry for the Stiletto STO-6X variant
  12. 12.0 12.1 Technical Readout: Prototypes, p. 103: "STO-6S Stiletto"
  13. MUL online entry for the Stiletto STO-6S variant
  14. BattleMech Manual, p. 95: BattleMech Quirk Table - Stiletto Entry.