TATRA STB-401 series is one of the most demanded shotgun with auto-regulating gas-operated system and rotating bolt. It uses two self-cleaning stainless steel pistons located just ahead of the chamber to function opposite a rotating bolt, thereby eliminating the need for the complex mechanisms.

The STB-401 is self-regulating for use with shotshells of varying lengths and power levels. It can fire both light-load and heavy-load magnum shells of differing propellant loads without any adjustments. The sights are military-style ghost ring and are adjustable in the field using only the rim of a shell. The picatinny rail on the receiver allows use of both optical sights and night-vision devices, while retaining use of the conventional sights.

The steel components of the STB-401 feature a matte phosphated corrosion resistant finish while the aluminium parts are matte hard-anodized. Its 18.5″ (47cm) barrels are made of 4140 drilled steel and chrome-plated inside, and outside immersed in phosphate, while the receiver is machined from 7075-T6 aluminium, which provides lightness and robustness together.

The STB-401, produced as a self-defense and duty weapon, preferred by the individuals and law-enforcement requires little maintenance and operates under any conditions.