Cory, that is Thermo Loc and it is sold by the GRS Corp. It is a plastic that you can heat and it will soften and let you set your piece into it, when it cools it hardens back up and locks your piece in place. To remove your work you just heat it up again to soften and release the part. I use a heat gun to heat it. The best part is that it is reusable. It's not cheap but it works great.