the stuff that i bought can from lowes and the sticker / tag has PGLA 118 on it. im assuming that the PG stands for Plexiglas. know what has me worried is that their is a site for building sumps and i just happen to find it today (know that im done with mine). on the site it says "You want acrylic, not plexiglas - the stuff Home Depot sells. Plexiglas ages, turns yellow, gets brittle, and cracks. Acrylic is harder, and you can buy various thicknesses."