Panthers and Tigers accounted for only 30% of the 2,300 German tanks deployed in Normandy; the rest being Panzer IVs, Sturmgeschütz IIIs and other tanks that the 75 mm gun Shermans were able to effectively handle. However, the importance of Caen and Montgomery's operations, which pinned German armoured forces in front of the British positions so the American units could break out to the west, meant that British and Commonwealth units had to face over 70% of all German armour deployed during the Battle of Normandy, as well as over half of the elite, well-equipped Waffen-SS "Panzer" units. As a result, the Sherman Firefly was perhaps the most valued tank by British and Commonwealth commanders, as it was the only tank in the British Army able to reliably penetrate the frontal armour of Panthers and Tigers at the standard combat ranges in Normandy.