The PT-91 Twardy is a Polish main battle tank developed as a modernized version of the Soviet T-72M1. It features improved armor protection with ERAWA explosive reactive armor, a modern fire-control system, and a more powerful S-12U diesel engine for enhanced mobility. The PT-91 retains the 125 mm smoothbore gun of its predecessor but incorporates upgraded electronics and communication systems, making it more effective and reliable in modern combat conditions.