The Classic 22 is a full-sized P220 while the Mosquito is modeled on the P226 but is 90% of the size. Another difference is that the Classic 22 is manufactured by SIG Sauer while the Mosquito is made under license by German Sport Guns GmbH. The size difference means that the Mosquito cannot be converted "up", and full-size SIG Sauer pistols cannot use the Mosquito's slide assembly. The SIG P225 is a more compact version of the SIG P220. A new German police standard issued in the mid-1970's prompted SIG-Sauer, Heckler & Koch, and Walther to develop new pistols that met the standard: the Walther P5, the SIG-Sauer P225 (known as the P6) and the Heckler & Koch P7. (In addition, Mauser had a design, the HsP, that never went into full production.) Walter Ludwig was involved in the design of the Walther, SIG-Sauer and Mauser entrants in the German Police selection. Each German state was free to buy whichever pistol it wanted to. Initially, the P220 was submitted; the P225/P6 was a revision created to conform with the mid-1970s West German police requirements for its standard service pistol. The SIG-Sauer P225 was the least expensive (due mainly to the inventive design) and received the majority of the orders. To be able to manufacture that many handguns, SIG acquired a controlling interest in J. P. Sauer & Sohn in Eckernförde, Germany to manufacture parts for the P220. This is also where all P225s were manufactured. The only difference between the P6 and P225—the P225 (which was adopted by US civilian law enforcement) has a lighter trigger pull, whereas the P6's trigger pull is heavier. The P225 has tritium fixed sights; P6s had fixed sights only. Genuine P225s manufactured for the West German Police will have a "P6" stamp on the right side of the slide. A new police standard was adopted in Germany in 1995, and the P225 is in the process of being replaced. German police pistols can be identified by the hammer, which has a small "ear" or "hook". According to section 7.7 of the German manual, the cutout is the "Deformationssporn", which means "deformation spur". This was a requirement of the West German Police for all their P6 pistols, to alert police armorers if the pistol was dropped on its hammer.