S-n-L, I use 2" X 10" X 8' Douglas Fir wood blocks! I buy the wood at Lowes, and I have them cut them into 2' sections. Lowes does 3 cuts for free, which makes 4-2' boards and no cutting or hauling a long board home! I've used everything and this works the best for me. And they won't wear out in my lifetime. I really like how they work in soft ground and in the heat (where my jack would damage the asphalt) they disperse the weight of my coach and transfer it evenly thru the 2" X 10" board. Good Luck in whatever you choose.