Accurate reference model.

"The 'Wasp' key-fob gun was manufactured by the Bulgarian company Bulforce-Milex with the model designation ‘OSA20’ and sold for self-defense purposes. These are designed as multi-purpose guns capable of firing both 8mm blank and irritant cartridges. In addition, an adaptor can be screwed into the muzzles of the device for the discharge of pyrotechnic signal flares. Originally a partial obstruction in the form of a pin would be present in each barrel and would prevent the discharge of projectiles, but allow the forward venting of irritant substances such as 2-chlorobenzalmalononitrile (CS). 

In May 1998, airport security around the world received an Interpol alert about these key fob guns. Unsuprisingly some of their users, followed by criminologists, quickly realized that the design lended itself to being converted to fire small calibre centerfire ammunition with ease. According to the American BATF, .32-caliber bullets, when fired from such a “key fob” can inflict fatal wounds at a distance of up to 20 yards (18 m). The conversion of these devices is relatively straightforward. The partial blockage is removed, and a steel lining is fitted into each chamber. In this converted state, it is possible to fire conventional .32 ACP and more commonly .25 Automatic (6.35 mm Browning) cartridges. 

The first converted key-fob blank and gas cartridge firing pistol submitted to the UK national forensic laboratory was from an incident dated October 23, 2003 and between then and 2008 a total of 31 were entered onto NFFID ( National Firearms Forensic Intelligence Database.). In 2005, in Manchester, UK, a 19-year-old mortally wounded himself in the head while displaying such a "keychain" in a nightclub. In December 2007, one Mark Henry, 27 years old, received received nine years in prison after wounding Yaw Darko Kwakye, 24 years old, in a London nightclub. In December 2010 during a murder hearing in Istanbul, the defendent was seriously wounded by a 6.35 mm bullet fired by the victim's brother who despite the presence of security managed to conceal a copy of the weapon into the courtroom.

The compact device consists of two main parts including a barrel block featuring two side-by-side barrels and breech block connected using a sliding dovetail mount and retained by a spring-loaded stopper located between the chambers. The trigger mechanism has two strikers and two trigger buttons. The cocking of the strikers is carried out by a centrally located connector bar which is pulled back with the help of a key ring fixed to it. At the rear end of the rod is a sleeve with side protrusions which served as a safety: depending on the rotation of the ring, it allowed or did not allow the cocking rod (and, accordingly, strikers) to reach the forward position. The rear retaining block was fastened at the back via two side screws. The barrel block and trigger block are made of aluminum alloy, with everything else being made of steel."