This is the current model of the RS-540, a long-selling Mabuchi motor that is familiar with plastic models and model crafts. (Diameter 1.4 inches (35.8 mm), 4.5 V - 9.6 V, 6.1 A); Uses a carbon brush, and is a full-purpose DC motor that is used not only for RC and models, but also for electric tools and household appliances. (For models, it is large enough for a large current flow. Does not work with small batteries. )