I've been searching for 2 days. I see it mostly in newer acrylic tanks, but I'm looking for the word for a part. I want a black plastic squared U shape piece in which to put my heater and filter intakes. Kind of like an upside down overflow, with the "teeth" down on the bottom to let water in. Inside that channel is my heater and filter intake. Instead of seeing them, the black plastic piece hides them against the back of the tank (which is painted black). Does that make any sense? Anyone have any idea what I'm talking about? I know i've seen them in people's tanks, I just can't find any pictures right now. /searchfail Thanks!