The PT-91 Twardy is a Polish main battle tank. A development of the T-72M1, it entered service in 1995. The PT-91 was designed at the OBRUM and is produced by the Bumar Łabędy company, part of the Bumar Group, a Polish technical military consortium. Changes from the T-72M include a new dual-axis stabilized fire-control system, reactive armour, a more powerful engine, transmission and new automatic loader.