Enduro motorcycles closely resemble motocross, or "MX" bikes (upon which they are often based). They may have special features such as oversized gas tanks, engines tuned for reliability and longevity, sump protectors, and more durable (and heavier) components. Enduro bikes combine the long-travel suspension of an off-road motocross bike with engines that are reliable and durable over long distances, and may be fitted with oversize gas tanks for adequate range. Some enduro bikes have street-legal features such as headlights and quiet mufflers to enable them to use public roadways. The engine of an enduro bike is usually a single cylinder 2-stroke between 125 cc and 360 cc, or 4-stroke between 195 and 650 cc.