The Beretta 21 Bobcat is a simple blowback pistol with a Single action/ Double action mechanism. It is fitted with a frame mounted thumb safety. The frame is made out of aluminum alloy, the slide and barrel are either carbon or stainless steel. The defining feature of this pistol is the 'tip-up' barrel. The barrel pivots on a pin under the muzzle so that the chamber may be loaded with the slide in the closed position. This simplifies loading as well as checking the load status as the slide is difficult to retract by hand.
The Bobcat 21 is available in either .22 LR (with 7 round magazine capacity) or .25 ACP (6.35 mm) (8 round magazine capacity) caliber. The .22 LR version is available in either black or stainless steel (called Inox by Beretta) versions, whereas the .25 ACP model is available in black only.