Trucks come as a pair. 

Size information: 

00 - 6.5" axle - for decks 6.5" or smaller

11 - 7.25" axle - for decks 7" - 7.3" 

22/02 - 7.6" axle - for decks 7.12" - 7.75" 

33/03 - 8" axle - for decks 7.75" - 8.12"

44 - 8.35" axle - for decks 8.12" - 8.5"

55 - 9" axle - for decks 8.5" - 9.12" 

66 - 9.35" axle - for decks 9.12" - 9.62"