As with the PzKpfw I, when the PzKpfw II entered service in 1935 it was meant to be used only as a training and development tank. In the event it had to be used as a combat tank from 1939 to 1942 simply because there were not enough combat tanks to replace the type, which acquitted itself well enough despite the fact that its main armament was limited to a 2-cm cannon: by 1941 the PzKpfw II was overdue for replacement as its armament was not able to penetrate other than soft-skin targets and the small turret ring could not accommodate a heavier weapon. However, the production line for the chassis was still in being and at the time it seemed to be too valuable to waste so the opportunity was taken to convert the PzKpfw II to a Panzerjäger. The prototype of this new Panzerjäger was fitted with a 5-cm (1.97-in) antitank gun, but the full production version was fitted with a special version of the 7.5-cm (2.95-m) Pak 40 anti-tank gun known as the Pak 40/2. This powerful gun was the German army's standard anti-tank weapon and the incorporation of greater mobility added considerably to the gun's anti-armour potential. The gun was placed behind a 10-mm (0.39-in) thick armoured shield that sloped to the rear to provide the gun crew with adequate protection, To accommodate the weight of the gun the engine was moved to the rear of the hull and the engine covers were used as a working platform to serve the gun. The vehicle was known as the Marder II (Marder meaning marten) although other and more cumbersome designations (such as 7.5-cm Pak 40/2 auf Slf II) were used on official documents.
The Marder II remained in production until 1944 and became one of the most widely used of all the many German self-propelled gun conversions. In production terms it was manufactured in greater numbers than any other weapon of its type, for 1,217 were made, The Marder II was certainly a handy and efficient weapon in combat for it was relatively small, had a good cross-country performance and the gun could knock out virtually any enemy tank other than super-heavy Soviet tanks such as the IS-2. Racks for 37 rounds were provided over the engine covers and there was also space for stowing 600 rounds for the machine-gun usually carried; this was a 7.92-mm (0.312-in) MG34 or MG42.
Most Marder II production was sent to the Eastern Front, but the Marder II was found wherever German troops were in action. By 1944 the type was out of production and the crew was often reduced by one man to conserve manpower, but the development of the type did not cease. During the latter stages of the war some Marder Us were equipped with infra-red searchlights for engaging targets at night and some of these equipments were used in action on the Eastern Front during the last stages of the war. By then such novel equipment could have but little impact on the outcome of the war.
Marder II | Crew: 3 or 4 | Weight: 11000 kg (24,251 lb) | Powerplant: one Maybach HL 62petrol engine developing 104.4 k W(140 hp) | Dimensions: length 6.36 m (20 ft 10.4 in); width 2,28 m (7 ft 5.8 in); height 2.20 m (7 ft 2.6 in) | Performance: maximum road speed 40 km/h (24.8 mph); road range 190 km (118 miles); gradient 57 per cent; vertical obstacle 0.42 m (16.5 in); trench 1.8 m (5 ft 11 in); fording 0,9 m(35 in)