The PT-91 Twardy (“resilient”) is a Polish main battle tank. A development of the T-72M1, it first entered service in 1995. The PT-91 was designed at the OBRUM (OBRUM for Ośrodek Badawczo-Rozwojowy Urządzeń Mechanicznych – Polish for Research and Development Centre for Mechanical Appliances) and is produced by the Bumar Łabędy[dead link] company, a part of the Bumar Group[dead link], a Polish technical military consortium. Changes from the T-72 include a new dual-axis stabilized fire-control system, reactive armour, a more powerful engine, transmission and new automatic loader. Unlike many other T-72 upgrades, the Polish Army PT-91s are upgraded using elements created almost exclusively by domestic companies, including a new engine, the fire control system and all communication system elements. Many of those elements were used to upgrade existing fleets of T-72 tanks in countries including the Czech Republic (T-72M4 CZ), Georgia (T-72SIM-1) and India (T-72 Ajeya Mk. 2).
Additional Information: en.wikipedia.org/wiki/PT-91_Twardy