This bundle includes everything you need to make the switch over to the Hot & New "Mini" Sprockets. 
Includes:
40MM Axle Hub
Aluminum Chain Guide Kit
3 Sprockets - Please Specify Sizes separated by a comma in the Customization Field
EX: {#219 45T, 46T, 47T}
Available Sprocket Sizes to choose from: (#219 45T-60T and #35 40T-50T)