Black foam/wood triangles? What are these called?

I've got two of these gigantic black foam/wood/stretched fabric(?) triangles... all I know is that they were used in a home theater. To absorb bass frequencies. However... what are these called? What is the Google-able name for these? I was thinking about putting them up here for sale but I'm at a loss...

Any help would be appreciated :)
Google "bass trap" or "acoustic panels."
Depending on the firm that manufactured them. I use GIK and tey are called tri-traps:
Corner traps