Glock pistols have a 'safe-action' trigger mechanism, which is neither single-action nor double-action, although it has been referred to as both 'double-action-only' and 'single-action' in literature. MOS (Modular Optic System) feature is available on the following models: 17, 19, 34, 35, 40, 41 and 45 add $40. NOTE: Add $70 if equipped with Meprolight night sights $90 if equipped with Trijicon night sights $30 if equipped with adjustable sights 10 percent for Gen4 if NIB.

Upgrades and changes for Gen5 include the Glock Marksman Barrel (GMB), with enhanced polygonal rifling, improved barrel crown, ambidextrous slide stop levers, a variety of sight options, flared magazine housing, no finger grooves on the grip and a tougher more durable 'nDLC' finish. In 2017, Glock continued the evolution of its product line and introduced Generation Five (Gen5) beginning with the Model 17 and Model 19. Gen4 features include three interchangeable back-straps, reversible magazine release button, improved recoil spring assembly and rough-textured frame (RTF) to enhance grip traction. In 2010, Gen4 (fourth generation) of Glock pistols was introduced. Common features include a striker-fired action with a consistent DA-only trigger pull, trigger safety within main trigger, no grip or thumb safety, polymer frame with integral grips and steel slide. Offered in many models, but main differences are caliber, sighting systems, barrel, slide and grip length, and magazine capacity.

Completely manufactured in Austria until 2004 when Glock opened its plant in Georgia to produce polymer frames.

Used gun values by serial number