Downhill longboarders usually use Reverse Kingpin Trucks (RKP), whereas skateboarders use Traditional Kingpin Trucks. RKP trucks tend to hold traction better and are easier to handle at speed, whereas TKP trucks are more suited for tricks, bowl skating and usually sport a lower ride height. Other forms of trucks have been seen in the downhill but remain on the sidelines. These would include torsion trucks (seismic) and CAM trucks (Other Planet). Downhill trucks are separated into two further categories: Cast and Precision. Cast trucks are the economical choice as well as the most common, although Precision Trucks are becoming more common. Cast trucks are usually a gravity cast aluminum with a solid steel axle that is non-removable. Due to the casting process cast trucks have 'slop' which is caused by small gaps in between parts. This causes small shifts and movements at speed and results in slightly diminished control. Cast trucks are also prone to warping slightly, causing uneven contact pressure on the wheels. Precision trucks can counter these limitations at a much higher price tag, although not all brands achieve this equally. Precision trucks are milled out of Aluminum billet and usually house two separate axles.