Disc Golf Discs are categorized into 3 separate types: Putters, Midrange and Drivers. All discs are categorized by speed, which is the 1st number in the set of flight numbers. 

Putters have a speed of 1-4. Discs with a speed of 4 are typically considered to be an approach disc but falls into the Putter category. 

Midrange discs have a speed of 5

Drivers are ranked speed 6 and above. Discs with a 6-8 speed are considered to be fairway drivers. Manufacturers rank their 9 speed discs to be either a fairway or a distance driver. It depends on which manufacturer we are talking about. Distance drivers are speed 10 and above and can be the most difficult to throw.