The Sherman Firefly is a British medium tank. Based on the M4 Sherman, it’s swapped the main gun for the British 17 pounder. Initially planned to be only a stopgap measure, it proved its effectiveness against Panthers and Tigers in Normandy.
The Firefly has superior anti-tank capability compared to most other tanks in its class. It comes at a cost as the Firefly is inferior to the standard Sherman against softer targets such as infantry and light vehicles.