SNK's first venture into the handheld gaming market came in the shape of the Neo Geo Pocket released on October 27, 1998 in Japan. The Pocket was a 16-bit grayscale handheld meant to compete with Nintendo's Game Boy. The main selling point of the unit would be fans' confidence in SNK and their quality line of games. As with many other consoles before it, however, games were released later than expected, which left the NGP with a very small initial library of games. The release of Samurai Shodown in December of that year was an encouraging step forward. SNK still needed to have an edge over their main rival, which prompted them to release a color version of the NGP.
The Neo Geo Pocket Color (NGPC) was released in March 1999 in Japan and showcased an impressive reflective 4K color TFT screen with approximately 40 hours of running time powered by just two AA batteries. King of Fighters R-2 was available at the time of the NGPC's release and was the first game to have the option of connecting to the Sega Dreamcast. The American release soon followed in June along with three highly-anticipated titles: Samurai Shodown 2, Metal Slug: First Mission and Fatal Fury: First Contact. Shortly after that, SNK released a new version of the NGPC dubbed New Neo Geo Pocket Color with a lighter and physically smaller design.
Source: Cyberia http://www.cyberiapc.com/vgg/neogeo_pocket.htm