[2][1] The pistol fires 9 mm cartridges, or bullets, which are similar to the American .40 caliber.
[2] The trigger on a single-action pistol releases the cocked hammer, striker, or firing pin, and performs no other mechanical function.
[9] The Walther Q4 SF uses a striker, which is a spring-loaded firing pin, rather than a hammer.
[1] The combination of a striker-fired, single-action pistol allowed Walther to adjust the trigger pull based on the perceived shooter's requirements and not the pistol's mechanical needs.
[1] The pistol comes with high visibility sights, which are designed for quick target acquisition and low light.