I have found them very useful for smaller jets, have Klett wheels on all my EDF's, I have dual 1" Kletts on a EJF F-18, they really help on the looks department with the hub holes and the flat threads. The only place I seem to always find them at is Grave's RC in Orlando, I fly to Florida at least once a year, everytime I stop at Grave's and buy a few, I have found I can never have too many of them...