Speed is the part of a disc golf flight number. This number represents how fast the disc must be thrown for the other flight numbers to be accurate. If a disc is thrown with more or less power (speed), the disc will fade or turn more than other flight numbers show. A disc thrown faster than it's flight number will overturn. With less power will under turn. Generally, putters are speed 1-3, approach discs are speed 4-6, Fairway drivers 7-9, and drivers are 10+.