I have three bags of
Lynx Levelers (Amazon). Two of the bags we've had now for 3 RV's (TT, 5er, and now the Axis)--they've held up quite well.
I've also picked up a set of the
double wide blocks (Amazon) for the rears. So far we've had these for two seasons now with satisfactory results (they are still together).
Thirdly I have a
set of these (also Amazon) for when we park the RV at the house. These seem to be fairing a little worse than the above blocks but are still functional at this point (have had them for 2 or 3 seasons now).