The Jagdpanzer designs followed on from the more lightly armoured Panzerjäger ("tank hunter") designs, which took an anti-tank gun and mounted it on top of a tank chassis with supplementary armour fitted around the gun crew. However, the armour had an open rear and top, almost never providing the crew with full protection from the elements. In addition, much experience was gained from the Sturmgeschütz series of assault guns for infantry support, which already used heavily armoured casemates, completely enclosing the vehicle's crew.