The most common scooters today have two hard small wheels, are made primarily of aluminum and fold for convenience. Some kick scooters have 3 or 4 wheels, or are made of plastic, or are large, or do not fold. High performance trickster scooters made for adults resemble the old "penny-farthing" with much larger wheel in front. Electric kick scooters differ from electric scooters in that they also allow human propulsion, and have no gears. Range is typically about 5 km, and maximum speed is around 30 km/h.