With an overall length of 168 mm (6.6 in) and height of 132 mm (5.2 in), and weighing approximately 710–770 g (25–27 oz) empty (depending on caliber), the P239 has become popular in the United States as a concealed carry pistol. Normal magazine capacity is 8 rounds (9 mm) or 7 rounds (.357 SIG or .40 S&W).
The actions available are double action only (DAO) or double/single action (DA/SA), as well as the newer DAK trigger system developed for law enforcement, which functions as a DAO trigger with a 6.5 lb (29 N) trigger pull. DA/SA pistols have a de-cocking lever on the left side of the frame in front of the slide-release. This lever lowers the hammer from cocked to de-cocked and engages a firing-pin safety, making the pistol safer to carry. With the hammer in the down position, the pistol can be fired by just pulling the trigger.
A concealed carry version is offered called SIG Anti-Snag or SAS. It has a dehorned stainless steel slide with custom SIG wooden grips and the DAK trigger system. The "Generation 2" of the SAS variant features a DA/SA SRT (Short Reset Trigger) trigger and night sights, but with slimmer polymer grips.
The P239 Tactical version of the pistol features a black Nitron finish, a 4 inch threaded barrel, SRT, and night sights.
A P239 with a "G" in the model number indicates the gun was issued to law enforcement and includes three magazines with the pistol.