Got a trailer from a buddy for cheap that is on its last leg but still works fine.  The bearings, tires, on it all were shot.  I ordered a complete set of tires with rims from Amazon and also this bearing set.  Installation was very straight forward however I found that a 3 jaw puller was essential to completing the job and getting the old bearings off the axle.  The old bearing  If you are new to this you want to make sure you have the following: