Panzer III addition, to counter enemy anti-tank rifles, starting from 1943, the Ausf. L version began the use of spaced armour sideskirts and screens (known as "Schürzen" in German) around the turret and on the vulnerable hull-sides. However, due to the introduction of the upgunned and more-armoured Panzer IV, the Panzer III was, after the German defeat at the Battle of Kursk in the summer of 1943, relegated to secondary/minor combat roles, such as tank-training, and it was finally replaced as the main German medium tank by the Panzer IV and the Panzer V Panther. The Panzer III's strong, reliable and durable
Mk 2 grenade replaced by the silent and more reliable 4 to 5 second delay M204 or M204A1 fuse. Due to the large number of grenades already issued, few grenades with the new fuses were used in combat during WWII. The original Mk 2 grenade had a threaded plug in its base, which covered the opening used to place the explosive filling, either of TNT, of Trojan explosive (a mixture of 40% nitrostarch, ammonium nitrate, and sodium nitrate), of a 50/50 amatol/nitrostarch mixture, or of Grenite (a mixture of 95% nitrostarch and binders). Some early Mk 2 grenades were filled with of smokeless