Raise my subwoofers off the ground approximately 12”?

I’m looking for some sort of subwoofer stand to raise my subwoofers off the ground about 12”.

Any ideas for building something or buying?
How much do you want to spend? I once had some really cool Hales two-way speakers that didn't achieve focus until I placed them on chairs in my living room. There are available stands (look at stands for Harbeth 40.1) and if you want to go nuts, go to a maker of monuments (headstones) had have some granite carved.
My REL 528 has a passive radiator on the bottom. Do I want them raised up? Any advice?