Thanks! That's exactly what it is. It's a 2' x 2' commercial suspended ceiling light unit. The last grow I did years ago was under this with the original 18w tubes in it. Very slow going as you can imagine! I've just recently ripped all the old tube light fittings/ballast/wiring from the unit before glueing the Reflect-a-grow on the underside of it (You can't see that in these pictures but there are pictures of the sheeting in my other posts) I'm hoping it'll work well once my young plants get going.