They have it in 3/4" for $11 and 1" for $13.

Because it is firm, it will compress on the edges where the plastic trim pressed down, but it will fill the void and support the glass bottom. Others have attemped to cut it to fit inside the plastic trim, but I find that to be unnecessary.

My glass tank does have some type of trim on it, but it was quite thin. It surely pressed into the foam somewhat.