From 1943 onwards vehicles were coated with a paste known as "Zimmerit" to prevent the attaching of magnetic anti-tank charges. This substance was applied by means of a spatula and then hardened with a blow lamp. Its use was discontinued towards the end of 1944 (Army Technical Pamphlet 1944, No 733).
In 1943 the improved Fliegerbeschussberät (antiaircraft mounting) 42 replaced the Fliegerbeschussberät 41. This could be fitted to the commander's cupola with clamps, which were also suitable for the MG 34 and 42. From 1943 onwards all newly completed tanks and all AFVs which had been repaired in Germany were fitted with smoke candle projectors.
From the end of 1942 10/ZW variants (i.e. Pz Kw III Ausf M) were re-equipped with the 7.5 cm gun L/24 (formerly the main armament of the Pz Kw IV). This gun was first installed as standard however in the final version of the Pz Kw III, Model N (Sd Kfz 141/2) (type II/ZW). A total of 64 rounds of 7.5 cm ammunition could be carried and 3450 rounds for the two MG 348. The total weight was 21,300 kg. Six hundred and sixty of these vehicles were produced. In August 1943, production of the Pz Kw III was officially terminated and the capacity now available was turned over to the building of assault guns.
In 1942 MIAG delivered 100 Pz Kw III Ausf M versions (type 10/ZW), without main armament, to the Wegmann factory, where these vehicles were converted into "Flammenwerfer-Panzer" (flame-throwing tanks). DKW two-stroke engines were used to drive the pumping system for the flame projectors. With an oil load of 1000 litres between 70 and 80 flame shots, each of 2 to 3 seconds duration were possible and flame length was between 55 to 60 metres. The steel flame projector, with a 14 mm nozzle was fitted into the mantlet in place of the usual 5 cm main armament. Both the coaxial and the hull MG were retained. The combat weight was about 23 tons and the crew consisted of three men. Wireless equipment carried was the Fu 2 and an Fu 5. Described as designated Pz Kw III (FI) (Sd Kfz 141/3), these vehicles saw service in special units.