"Be very wary of buying this product. The fitted bearings can only be used with a 5/8" axle (a standard size in the US apparently) though you only find this out after breaking-open the packaging.
For a larger axle, you have to hammer-out the bearings and make do with the supplied plastic bushings. These really only work with axles up to 3/4" and you will find that they cannot be made to fit a 20mm axle more likely to be seen in the UK. Having reached this point you can no longer return the item as-new for a refund.
The only solution I could find was to get an engineering firm to make me a new axle!"