These models are similar to the one you are viewing.
9mm Para. cal., DA/SA, similar to Model 439, only stainless steel, 8 shot mag., ambidextrous safety became standard 1986, 36 oz. Mfg. 1982-1988.
9mm Para. cal., DA/SA, 4 in. barrel, stainless steel slide and alloy frame, exposed hammer, 10 (C/B 1994) or 15* shot mag., adj. (disc. 1993) or fixed rear sight, ambidextrous safety. Mfg. 1990-1997.
9mm Para. cal., DA/SA, alloy frame, 12 shot finger extension mag., short frame, bobbed hammer, 3 1/2 in. barrel, sandblast blue or satin nickel finish, ambidextrous safety standard (1986), molded Delrin black grips, 26 oz. Mfg. 1983-1988.
9mm Para. cal., DA/SA, aluminum alloy frame, 3 1/2 in. barrel, hammerless, 8 shot finger extension mag., fixed sights only, ambidextrous safety, blue finish, straight backstrap grip, 25 oz. Mfg. 1990-1995.
9mm Para., .40 S&W, .357 SIG (disc. 2010), .380 (new 2014), or .45 ACP (new 2007) cal., DAO, SFO, black Melonite finished stainless steel barrel and slide with twin scalloped slide serrations, black Zytel polymer frame reinforced with stainless steel, matte black or Dark Earth brown (new 2007) finish, 6 (new 2014), 8, 10, 12, 15, or 17 shot mag., ramp front sights, Novak Lo-Mount Carry rear sight, ambidextrous manual safety became an option during 2009, 6 1/2 lbs. trigger pull, 18 degree grip angle, Picatinny rail in front of trigger guard, three interchangeable grip sizes, 24 1/4-29 1/2 oz. Approx. 25 variations in each caliber. New 2006.