Cars are powered by various sources. Electric cars are powered by small but powerful electric motors and rechargeable nickel-cadmium, nickel metal hydride, or lithium polymer cells. There are also brushed or brushless electric motors. Most fuel-powered models use glow plug engines, small internal combustion engines fueled by a special mixture of nitromethane, methanol, and oil (in most cases a blend of castor oil and synthetic oil). These are referred to as "nitro" cars. Recently, exceptionally large models have been introduced that are powered by small gasoline engines, similar to string trimmer motors, which use a mix of oil and gasoline. Electric cars are generally considered easier for the novice to work with compared to fuel-driven models, but can be equally as complex at the higher budget and skill levels.
In both of these categories, both on-road and off-road vehicles are available. Off-road models, which are built with fully-functional off-road suspensions, can be used on various types of terrain. In comparison, on-road cars, which generally have a limited or non-existent suspension, are strictly limited to smooth, paved surfaces.
Grave Digger (often referred to as simply Digger) is the name of a team of monster trucks currently racing in the USHRA Monster Jam series. There are several Grave Diggers being driven by different drivers to allow them to make appearances at more events, but their flagship driver is creator Dennis Anderson. Grave Digger is considered to be one of the most influential monster trucks of all time
