Trailer hub replacement

[Blue_Runner]

I want to replace my trailer hubs for peace of mind on long towing trips. I have a 2005 Venture dual axe trailer....w/ my V21 sitting on it......I was looking at the galvanized Super Lube hub kits. Looks like they get pretty good reviews and the install could not be easier...comes pre-greased w/ seals/bearings etc. already installed. How do I know what size/model number to get? Here is one I looked at on eBay. Thanks for the help!

http://www.ebay.com/itm/Tie-Down-Sup...#ht_1299wt_958