It's a porous media sold by SeaChem, it's just a brand name for a product.
I would stick with easy to keep livestock, get the tough common stuff.
Folks with the high maintenance touch stuff can keep it with work but common stuff can look very nice if you consider the over all aquascape.
A well placed common plant/algae or coral will look many times better than some rare/tough to keep species. It will also thrive and look healthier as well.
So on any given Sunday, you will have a decent looking tank.
Be careful about what you buy as far as livestock.
Regards,
Tom Barr