NASA-supported human-factors research is not the usual starting point for a pistol grip, but it is where CZ’s DiFEND methodology comes from, and it shaped the way the new CZ DUTY fits the hand. The rest of the pistol is just as deliberate. A serialized modular chassis holds everything together, a refined striker-fired trigger sits inside it, and the controls work for left- and right-handed shooters alike. The slide takes a red dot directly, with no adapter plates needed for four popular footprints. The CZ DUTY 4.0 lineup comes in four versions, with 15 or 17 rounds and with or without a manual safety.