Z scale is one of the smallest commercially available model railway scales (1:220), with a track gauge of 6.5 mm / 0.256 in. Introduced by Märklin in 1972, Z scale trains operate on 0–10 volts DC and offer the same operating characteristics as all other two-rail, direct-current, analog model railways. Locomotives can be fitted with digital decoders for independent control. Model trains, track, structures, and human/animal figures are readily available in European, North American, and Japanese styles from a variety of manufacturers.