Suntour stuff isn't easy to come by any more, but it was well made enough that there's still plenty kicking around. If you're one of the lucky ones who still has a Suntour bike, then you'll need the Park Tools FR-3 to remove the 4-notch lockring on your cassette. Features: Fits all Sun Tour four notch freewheels since 1986 The FR-3 has 4 notches approximately 24mm across 1" base fits wrench or bench vise