Manufacturer catalog

ST Ravne

ST Ravne is the catalog-facing Slovenian builder name attached to the M-55S tank modernization, a T-55 upgrade produced in Ravne na Koroskem with armor, fire-control, and NATO-caliber armament changes. Later Slovenian defense-industry sources tie the same industrial line to Sistemska tehnika and ARMAS, which supplied artillery components, torsion bars, vehicle integration, and maintenance work.

2 weapons

The ST Ravne builder facet appears in the catalog through the Slovenian Armed Forces' M-55S and M-55 USP equipment pages, which identify ST Ravne, Slovenia as the manufacturer for the upgraded T-55 family.

Slovenian defense-industry material lists ARMAS d.o.o. and Sistemska tehnika d.o.o. at Koroška cesta 14 in Ravne na Koroškem, with NCAGE 1133Q and work in artillery weapon parts, barrels, breech components, torsion bars, system integration, servicing, reconstruction, and upgrades of armored vehicles.

Corporate sourcing is not perfectly linear: SIJ says Sistemska tehnika changed its name to Ravne Systems in January 2016 after a takeover, while the Park of Military History describes Sistemska tehnika as a predecessor to Armas. This profile keeps ST Ravne as the catalog label and records the related spellings as aliases rather than creating duplicate builder pages.

Tank modernizationArmored vehicle integrationArtillery weapon componentsTorsion bars and suspension componentsVehicle servicing and reconstruction

Notable Systems

M-55S, Upgraded T-55 main battle tank, Tanks

M-55S

Upgraded T-55 main battle tank

Slovenian Armed Forces equipment data identifies the M-55S as an upgraded T-55 manufactured by ST Ravne, Slovenia, with a 105 mm gun, fire-control equipment, laser-radiation detection, and explosive reactive armor.

Sources: Slovenian Armed Forces armoured units
M-55S, Upgraded T-55 main battle tank, Tanks

M-55 USP

Upgraded T-55 main battle tank

The Slovenian Armed Forces list the M-55 USP driver-training tank under ST Ravne, Slovenia, as a turretless training derivative using the M-55 S vehicle basis.

Sources: Slovenian Armed Forces armoured units
Valuk, 6x6 wheeled armored personnel carrier, Armored Vehicles

Valuk 6x6 heritage

6x6 wheeled armored personnel carrier

The Park of Military History describes Valuk 6x6 prototype models as heritage of former Sistemska tehnika, a predecessor to Armas, while the Slovenian defense-capabilities catalog says Armas carries out regular maintenance on Valuk 6x6 vehicles.

Sources: Park of Military History Armas donation, Slovenian defence companies capabilities

Manufacturer History

  1. M-55S modernization

    ST Ravne is credited on Slovenian Armed Forces equipment pages as the Slovenian manufacturer of the M-55S upgraded T-55 tank and its M-55 USP training derivative.

    Sources: Slovenian Armed Forces armoured units

  2. Sistemska tehnika renamed within SIJ restructuring

    SIJ reported that Sistemska tehnika d.o.o. changed its name to Ravne Systems d.o.o. on 18 January 2016 after the SIJ Group and Ravne Knives completed a takeover.

    Sources: SIJ Ravne Systems restructuring notice

  3. ARMAS listed in Slovenian defense-industry capabilities

    A Slovenian Ministry of Defence capabilities catalog listed ARMAS d.o.o. and Sistemska tehnika d.o.o. in Ravne na Koroškem with NCAGE 1133Q and activity in artillery parts, torsion bars, system integration, service, and maintenance.

    Sources: Slovenian defence companies capabilities

  4. Museum source documents Sistemska tehnika heritage

    The Park of Military History described Sistemska tehnika as a predecessor to Armas and connected it to Valuk 6x6 and Krpan 8x8 vehicle prototype heritage.

    Sources: Park of Military History Armas donation

Predecessors
Sistemska tehnika
Successors
ARMAS d.o.o.Ravne Systems d.o.o.
Website links
ARMAS official websiteSlovenian Armed Forces M-55S equipment pageSIJ Ravne Systems restructuring notice

ST Ravne appears as the catalog manufacturer on Slovenian Armed Forces equipment pages, while later public sources use Sistemska tehnika, ARMAS, and Ravne Systems for related Ravne-based industrial activity. The profile treats those names as linked aliases with sourcing notes instead of merging them into an unsourced single legal history.

Manufacturer Sources

  • Slovenian Armed Forces armoured unitsPublisher: Slovenian Armed Forces | Note: Official equipment page identifying ST Ravne, Slovenia as manufacturer of the M-55S and M-55 USP and providing system role and specifications. | Accessed: 2026-06-21
  • Slovenian defence companies capabilitiesPublisher: Ministry of Defence of the Republic of Slovenia | Note: Government capabilities catalog listing ARMAS d.o.o. / Sistemska tehnika d.o.o. at Koroška cesta 14, Ravne na Koroškem with NCAGE 1133Q, website references, component-supplier activities, system integration, service, maintenance, and weapon-part product areas. | Accessed: 2026-06-21
  • SIJ Ravne Systems restructuring noticePublisher: SIJ - Slovenian Steel Group | Note: Corporate source for the takeover of Sistemska tehnika d.o.o., its 18 January 2016 name change to Ravne Systems d.o.o., and the planned merger with Ravne Knives and Serpa. | Accessed: 2026-06-21
  • Park of Military History Armas donationPublisher: Park of Military History Pivka | Note: Museum source describing Armas d.o.o. from Ravne na Koroškem, Sistemska tehnika as a predecessor to Armas, and former Sistemska tehnika military-vehicle heritage including Valuk 6x6 and Krpan 8x8 models. | Accessed: 2026-06-21
  • ARMAS d.o.o. registry profilePublisher: Bizi.si | Note: Business-registry profile for ARMAS d.o.o. with address, official website, legal name, and the former name Sistemska tehnika ARMAS, proizvodnja in trgovina, d.o.o. | Accessed: 2026-06-21
  • Slovenian manufacturers listPublisher: Army Guide | Note: Defense-reference manufacturer list showing both Sistemska tehnika Armas d.o.o. and STO Ravne, doo under Slovenia, supporting alias coverage for the catalog manufacturer facet. | Accessed: 2026-06-21
  • File:M-55S SV.jpgPublisher: Wikimedia Commons | Note: Image source for the M-55S tank, the cataloged ST Ravne modernization; file page lists author AndrejS.K, own-work source, and Creative Commons Attribution-Share Alike 4.0 licensing. | Accessed: 2026-06-21

Produced weapons

Category

Armored Vehicles

Troop carriers, infantry fighting vehicles, and protected mobility.

1/1
Valuk, 6x6 wheeled armored personnel carrier, Armored Vehicles2014 Russia-Ukraine WarValuk6x6 wheeled armored personnel carrierBuilt in: SloveniaThe Valuk is Slovenia's 6x6 wheeled armored personnel carrier derived from the Pandur family and associated with ST Ravne/Sistemska tehnika production and support. Slovenian Army material documents a ST Ravne LKOSV ambulance configuration with a 3+6 crew layout, 211 kW engine, 13.8-ton maximum mass, and 100 km/h road speed, while 2023 reporting documented Slovenia transferring 20 Valuk vehicles to Ukraine for the Russia-Ukraine War.

Category

Tanks

Heavy armor built around direct fire, protection, and battlefield shock.

1/1
M-55S, Upgraded T-55 main battle tank, Tanks2014 Russia-Ukraine WarM-55SUpgraded T-55 main battle tankBuilt in: SloveniaThe M-55S is Slovenia's modernized T-55 main battle tank, rebuilt by ST Ravne with a 105 mm gun, explosive reactive armor, fire-control upgrades, laser-warning equipment, and NATO-compatible ammunition. During the 2014 Russia-Ukraine War, Slovenia committed 28 of the scarce upgraded tanks to Ukraine through a ring exchange with Germany, turning a reserve Cold War chassis into a Western-supported Ukrainian fire-support vehicle.