After the 50mm KwK was introduced, two blue warning lights were mounted on the front wall of the bow armor in front of the tank driver. They served to inform the driver if, while the tank was underway, the 50mm KwK barrel extended over the outside limits of the vehicle when the turret was turned. The warning lights were switched on by a switch that was screwed onto the top of the bow armor in Ausf. E and F and built into the release-ring carrier of Ausf. G and subsequent types.
The introduction of 50 mm armor plate resulted in the use of a Fahrersehklappe 50 (Driver's Visor Flap 50), consisting of a housing screwed onto the front wall of the bow armor and covered by a sliding panel.
From the Ausf. J on, only the "KFF 2" driver's optics could be used. The "Kugelblende 50" ball mantelet was also used from Ausf. J on.
The racks and containers for the engine and weapons equipment and supplies carried in the upper part of the superstructure showed differences as to their location and the number of them used in types E. F. G, Hand J.
Outside, screwed onto the back wall of the turret (and retro-fitted to all Panzerkampfwagen Ill's), was a box that held the crew's packs.
In the bow armor of the hull there were, through Ausf. H, two divided, boltable entry hatches for the driver and radio-operator. Beginning with Ausf. J, there were only two one-piece servicing hatches. Through Ausf. H, there were two towing-hook attachments with bolts on each end of the tank's hull, to allow the vehicle to be towed, but beginning with Ausf. J there were only two welded-on eyes. Delbag air filters were used through Ausf. H; they were attached to the engine-compartment side of the bulkhead and linked with the carburetor by a forked tube. Beginning with Ausf. J, Mahle centrifugal oil filters located in the engine compartment were used; they were connected mechanically to the steering and support brakes, whereas through Ausf. K (Armored Command Vehicle) the connection had been hydraulic.
According to a message from the authorizing General in charge of motor vehicles, dated July 21, 1941, additional capacities and production facilities for expanded tank production were being set up. Among them were a Daimler-Benz AG factory, the Fahrzeugwerke Friedrich Krupp AG, Fross-Bussing in Vienna, Tatra Wagenwerk in Kolin, Framo in Hainichen, and branches of MAN, Henschel, Hanomag, Auto-Union and NSU.
In terms of quantities, there were 327 Panzer III tanks with the 37mm KwK gun and 1174 with the 50mm KwK in service with the army in the field as of July I, 1941. The number of tanks with the 37mm gun has decreased to 131 by April I, 1942, while the number of tanks with the 50mm gun had risen to 1893. The monthly production of "Panzer III" tanks for January 1942 had been set at 190 units, but in fact, what with transport difficulties involving guns and armor plate, only 159 could be delivered.
At the end of 1941 the second series of Panzerkampfwagen III, Ausf. J, with chassis numbers from 72 001 to 74 100, was delivered. This series finally had the 50mm Kw K L/60 gun as standard equipment.
The ammunition supply for these vehicles, now referred to as "Sd.Kfz.141/1", was cut from 99 to 84 shells, while the supply of 3750 machine-gun rounds remained unchanged. Until the installation of the long 50mm tank gun, all Panzer III tanks had a folding seat for the loader attached to the bulkhead that separated the fighting and engine compartments. This seat was then eliminated. During the course of Ausf. J production too, the vision ports and their flaps built into the right and left sidewalls of the turret, and the port flap to the right of the mantelet, were eliminated. Forty production vehicles with the 50mm KwK L/60 were delivered by the end of 1941.