Though several Philippine enterprises are involved in the manufacture of small arms, submachine gun production is mostly limited to copies of foreign designs such as the MAC-10 and the KG-9 assembled in clandestine workshops for sale in the black market. There are few openly marketed indigenous submachine gun designs owing to the availability and popularity of imported weapons such as the Israeli Uzi and the H&K MP5.
The Floro Mk. 9 submachine gun was developed as a private venture by Floro International Corporation, an ISO 9000 certified company providing precision manufacturing and digital/optical media services. It was offered for evaluation to the Armed Forces of the Philippines and the Philippine National Police. Initial responses were favorable and some sales were made, particularly to the AFP's Anti-Crime Task Force and the Philippine Navy's Special Warfare Group. The Philippine Marine Corps had a standing requirement for submachine guns to serve as personal defense weapons for armor crews and the Floro Mk. 9 was an option. Limited funds and the availability of M3 Grease Guns from reserve weapon stockpiles caused these to be issued instead. The M3 had the advantage of using the .45 ACP cartridge which is more widely used in the AFP and has greater stopping power than the 9×19mm Parabellum.
Floro International currently markets an updated Mk. 9 and a shorter, lighter version, the MP-9. It is believed to be formerly known as the MK-19 submachine gun.
The standard Mk. 9 is a blowback operated weapon chambered for the 9 mm cartridge. It fires from a closed bolt with a selector switch allowing semi-automatic or full-automatic fire. There is no bolt-locking mechanism. The upper receiver is a steel tube and the barrel is held in place by the perforated barrel jacket. The lower receiver and magazine housing are of sheet metal. The long magazine well has a plastic handguard and doubles as a forward grip. It has the Uzi submachine gun-type magazine interface and uses Uzi magazines which are locally available. The folding metal butt is based on the Uzi pattern as well. The Mk. 9 uses the firing mechanism of the M16, the standard service rifle in the AFP.
Speaking of the origin of the design, on the external look of the gun, there is a striking resemblance to the Federal Engineering XC series of semi automatic "assault rifle lookalike" carbines (marked 220, 450 and 900; in .22LR, .45 ACP and 9mm Para calibers respectively) produced in mid 1980s in the USA, approximately 20 years before the emergence of Floro MK 9 on the market.
It is undoubtly certain that the makers of Floro MK-9 studied the XC 900 carbine and based their design directly on it, although with some slight differences, addons and modifications that in some way improved the original design. One such improvement is usage of the Uzi magazine style catch in Floro magwell, rather than making modified Uzi magazines with welded steel insert at the top of the magazine, serving the purpose of catch retainer surface, as in the original XC 900. This decision to bind the users of the gun in buying only the company spare parts, certainly made logistic problems as it disabled the compatibility in using that particular magazine directly in Uzi (which cannot be put in the magwell due to the steel insert), or buying the standard 25- or 32-round Uzi magazine on the surplus market to be used as a spare one for XC 900 carbine. Other usable addon to the design is the Picatinny rail, allowing to easily place scopes and other equipment, which was in the original XC troublesome. Also sights are different, as the original ones were very user unfriendly when trying to zero them.
The cocking handle is on the left side of the upper receiver incorporated with a dust cover. The front sights are fixed and rear sights have an adjustment knob for windage. The upper receiver has a Picatinny rail installed allowing telescopic and red dot sights to be used.