I used regular gutter flashing for the 2 bulb units. For the 4 bulb units, I had some 22ga. brushed alloy aluminum pre-cut and bent so it would look more presentable (may not be in a canopy). I have a similar airflow to an ATI powermodul, only larger fans... and air is sucked in the top (or out if I reverse the fan... in my case I just plan on ducting the fixtures from outside the canopy when the canopy panels go on). The air goes in the top, and then hits the backside of the reflectors, so it flows out to each end of the reflectors, cooling the ballast(s) on the way, and then wrapping around the ends of the bulbs. Then, I dont have the pics up yet in my 'red house' thread, but there are acrylic sheilds in front of the reflectors that keep the air flowing over the bulb until the center where the acrylic sheild has a slot to let air out. Everything is protected, everything is cool, everything is light... and that coil flashing is cheap. Heck, a contractor buddy of mine had some left over from a roofing job that was coated in white PVC, so he bent up the fixtures for me on his break, and I hung them right up. If you wanted, you could buy or paint it any color you want, or just leave it as raw aluminum.