The U-94 UDAR (У-94 "Удар"; the Russian word udar means "Strike" or "Blow") is a police weapon designed and developed by the KBP Instrument Design Bureau in the early 1990s and first manufactured in 1994. It is a compact double-action revolver that chambers proprietary ammunition in the form of an unusual 12.3mm (0.484" caliber, or 41-gauge) shell. It has a shrouded hammer that can be manually cocked or decocked by use of a cut-out slot at the top of the shroud. It has a side-breaking cylinder that opens to the left and uses a star-ejector to eject all the spent shells at once.