A synthetic racetrack surface is any kin of surface substance that replaces dirt or sand as the racing surface on a horse racing track. Synthetic surfaces are desirable over traditional surfaces for several reasons, most prominently the reduction of injuries and subsequent deaths to horses because of less wear and tear on their legs, and improved racing conditions in inclement weather. Manufacturers of synthetic racetrack surface materials usually promote the fact that synthetic tracks have drainage qualities superior to natural surfaces, which enables track stewards to rate tracks as "fast" under conditions that would normally result in "slow," "sloppy" or "muddy" conditions. In more extreme conditions such as freezing weather, synthetic surfaces often allow racing to be conducted when it might otherwise be cancelled due to a frozen track.