getting height in aquascape

[quirkylemon103]

so I was watching a FW aquascaping video and he was using this thing to get height cheaply
could I use this in saltwater and do you know where to find it and what its called?

 

[Bepis]

I do not know what that but A lot of reefers use egg crate and pvc to lift theirs.

 

[Gtinnel]

I'm not sure what that is either but I'd bet there is a decent chance that it was 3d printed and not something that is readily available to buy.