Daewoo Precision Industries K5

The Daewoo Precision Industries K5 or K5/DP51 series is a 9×19mm semi-automatic pistol produced by S&T Daewoo of South Korea.
The K5 was introduced in 1989. It is recoil operated and uses a conventional Browning-type locking system. It is mostly carried by commissioned officers in the South Korean military.
Design.
The K5 is a compact, lightweight pistol with an unconventional trigger mechanism called "fast action". The frame is made of forged 7075-T6 aluminum alloy with a matte anodized finish, while the slide is constructed out of forged 4140 steel with a matte finish. The barrel is made of forged 4150 steel with a (6 grooves) right twist.
The pistol features an unusual "fast action" trigger mechanism which allows the hammer to be decocked while still keeping the mainspring compressed. The "fast action" (also known as Triple Action, and most recently known as Double Action Plus+) mode allows the trigger travel of the double-action mode and the trigger weight of single-action mode. This allows a more accurate first shot due to the lighter weight of the trigger. It is also safer due to the longer trigger travel required to fire the pistol. A light pull on the trigger causes the hammer to flick back, after which the pistol would behave in conventional single-action mode.
The pistol can also be fired in traditional double and single-action modes.
The factory double-column type box magazines hold 13 or 15 rounds for the full size variant or for the compact variant 10 rounds. Smith & Wesson 59-series magazines are known to be compatible with the DP51 but will protrude slightly. The magazine release is of the push button type.
The pistol has three-dot iron sights. The safety consists of an ambidextrous safety external safety and a passive firing pin block which (as its name implies) blocks the firing pin from moving forward unless the trigger is pulled.
The handgrip panels are made of one piece polymer.
Commercial sales.
The K5 was marketed commercially in the United States between the early to late 1990s through various importers, including FirstShot, Inc., Kimber of America, Inc., B-West Imports, Inc., and Davidsons, Inc. as the DP51, with a compact version known as the DP51C and S&W caliber version known as the DH40. 
It is most recently reintroduced through collaboration between Daewoo (now S&T Motiv) and Lionheart Industries of Redmond, WA in 2011 as the LH9, LH9C, and LH9 MKII (amongst other variants), featuring numerous updates including a redesigned hammer, wider slide serrations with added serrations to the front of the slide, redesigned grips, Cerakote finish, and optional Picatinny rail (as the MKII).
The internal design and basic functions remain identical to the original and all the parts interchange between the original and the Lionheart variants.