The SIG P229 pistol was designed as a conceal and carry weapon and is a very compact firearm. The standard models of this weapon feature a SA/DA trigger however are also available with a DAO trigger.
The HK P2000 or Heckler & Koch (H&K) P2000 and P2000SK are pistols based upon the popular H&K USP (Universal Self Loading Pistol). The weapon has an ambidextrous magazine release and slide locks.
The difference between the Glock 32C and the Glock 32 is that the slide and barrel are ported on the Glock 32C model to reduce muzzle climb while shooting the pistol.
The M&P (Military and Police) compact .357 SIG is a variant of the M&P Standard 9mm. See http://www.gunslot.com/guns/smith-wesson-m-p-standard-9mm for full details on the firearm.
The Glock 31 is a pistol produced and manufactured by the Austrian Glock Company. It is essentially a Glock 22 modified to fire the larger .357 SIG ammunition.
HS Produkt (formerly I.M. Metal) manufactures these weapons in the city of Ozalj, Croatia and then licenses and sells the weapons in the US by Springfield Armory.