After the Second World War, Czechoslovakia's Ministry of the Interior requested a new pistol design from Česká zbrojovka Uherský Brod. The resulting gun was chambered in .32 ACP and designed by two brothers Jan and Jaroslav Kratochvíl. It combined elements from both the Walther PP and PPK. The pistol is fed from an 8-round single-stack magazine, located within the bakelite paneled grip. Small fixed sights are located on top of the slide. The pistol functions via the blowback principal - recoil causes the slide to move backwards, thereby compressing a spring around the fixed barrel. After it reaches the end of its rearward travel, the recoil spring returns the slide to its forward position, stripping and chambering a new round from the magazine as it does so, rendering the gun ready to fire again. Hammer and trigger operation is double-action - that is, the hammer can be cocked and released by a squeeze of the trigger.