Sprockets and cassettes are parts of every bike shifting. The distinguishing feature is that cassettes consist of several sprockets. For this reason, cassettes are also referred to as sprockets. Sprockets are used on bicycles with derailleur gears. The installed cassettes are narrower with increasing number of gears, since the existing space on the rear wheel is always about the same. In contrast, sprockets are more pronounced for bicycles with hub gears or single speed bikes, as the focus is on safe chain guidance and durability.