HUB KIT.. 1 ''    FOR THE SEVEN SPEED FREEWHEEL HUBS...THERE ARE BOLTS NUTS AND INSTRUCTIONS ON HOW TO INSTALL.
YOU MUST  USE STOCK NINE BOLT STEEL SPROCKET THAT COMES IN THE ENGINE KIT   ( PLEASE NOTE WHAT I AM SELLING IS IN PHOTO # 2  NO SPROCKET IN KIT ) 

THIS PART DOES A GREAT JOB IN  KEEPING YOUR SPROCKET TRUE CONCENTRIC  ..AND SQUARE TO HUB SUPER EASY TO INSTALL ON SEVEN SPEED SHIMANO...HUBS

AND A LOT OF OTHERS MAKE SURE YOUR  OUTSIDE  DIAMETER IS 1 INCH  LOOK AT PHOTO'S TO UNDERSTAND WHAT AND HOW IT WORKS BORE SIZE ON MY HUB HERE IS SIZE 1.000  +./- .002     IT  FITS  A LOT OF FREE WHEEL HUBS.....