This personal-sized (in SIG Arms terms) handgun is made in USA at SIG Arms factory. Technically it is similar to P228 compact gun, and differs only in size and magazine: while P228 has a dual-stack magazine for 12 rounds, P239 has a single-stack magazines for 7 or 8 rounds (depending on caliber).
P239 is a blowback-operated, locked breech design, with modified Browning-style linkless locking via slide ejection port. It has same DA or DAO trigger mechanism with striker pin safety, manual decocker (lever on the left side of the frame), slide stop. Slide is machined from solid steel. Frame is made from aluminium alloy.
P239 is reliable like all its bigger brothers from P22x family, and very accurate for its small size. It may be not so light, but packs a lot of firepower in compact package and is very popular as a concealed carry and police backup or off-duty gun.