all in one

Hello all. What is the name of the foam that you put underneath the aquarium to prevent seen and unseen imperfections in the stand surface, from causing torsion related tank damage? I picked up a cheap 29 gal from petco ($40...50% off sale) as I don't want to wait a year to afford a decent used...

I'm changing a lot of stuff around in the reef room. Follow along if your into this type of thing.