Please note: A set of these guards is already included with your BikeBox! 
 
The guards are especially designed protective inners to cover cassette, crank, rear derailleur, skewers and wheel hubs to make sure your bike is completely safe during transport. 
The inners are individually shaped pieces of Polypropylene which slide and fold around the respective components. Made from a sturdy and waterproof material - they form a protective casing.