The prototype of modern "cube" was a satchel wz. 1925, used by the Polish Army since the mid-20s The twentieth century. It was the first military backpack domestic production, based on backpacks Reichswehr of the First World War . Square, dyed denim backpack was the color of tea, and on the outside of the flap was sutured with a distinctive square bars, which was attached to the canteen . The leather harness and straps was modeled on the German original. Belts mounted on a special metal rail, slide-on top of the back of the backpack. Four metal brackets mounted on the sides and top allow przytroczenie coat or blanket.
Soon after the backpack to equip started work on its improvement. First of all, it was about backpack weight, and to improve the material from which it was made. The work resulted in the introduction of the backpack mod. 1927, and ultimately an improved version of wz. 1933, sewn with canvas Polish production (linen impregnated with copper salts). The latest version was characterized by, among others, parcianymi suspenders and belts. Although planned to equip the entire army in backpacks last type, the 1939 defensive war remain in use all three types.