Leveling blocks for a DP

We tried the horse mat route and it didn't work. When you stack a few of them up the jack just sinks into them. They do work to keep the damp from the jacks. We used 2x8 and had them cut to size. If they get ruined we can just throw them away and get new ones.

I saw these at an RV show and they looked like they would work but are fairly expensive.