The PT-91 Twardy is a Polish main battle tank. It is a development of the T-72M1 and first entered service in 1995. The PT-91 was designed at the OBRUM and is produced by the Bumar Łabędy company - part of Polish military consortium - Bumar Group. 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 . Many of those elements were used to upgrade existing fleets of T-72 tanks in countries like in Czech Republic - T-72M4Cz, Georgia - T-72SIM-1 or India - T-72 Ajeya Mk2.