Z Scale trains are the smallest commercially available model train scale in the world, (aside from Tgauge) introduced by Märklin of Germany in 1972. Operating at a ratio of 1:220 to real-world size, Z Scale track has a gauge (rail-to-rail width) of only 6.5mm, and locomotives typically measure just 4–8cm in length, making them small enough to fit an entire layout inside a briefcase. Despite their tiny size, Z Scale trains are highly detailed and fully functional, running on 0–10 volts DC. The scale's compact footprint has made it popular among hobbyists with limited space. Major manufacturers include Märklin (the originator of the scale), Rokuhan of Japan, AZL (American Z Lines) which specializes in North American prototypes, Full Throttle of Leesburg, FL which specializes in freight rolling stock, and Micro-Trains Line, which was recently purchased by Atlas, and produces both rolling stock and accessories. Smaller or boutique producers such as Z-Stuff for Trains and Ztrack also contribute to the hobby, offering a range of locomotives, freight and passenger cars, and scenic accessories that allow modelers to build remarkably detailed miniature railroads in a very small footprint.