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Whatever Home Depot or Lowe's carries. I did a bunch of Clopay doors from Home Depot at $300 for a full kit...cheaper than you can make yourself. Very easy for most anyone to assemble and completely install. Un-insulated for detached garages and Insulated for attached or built-in.
1 I had done got mangled by an idiot with a bulldozer, he used the door as a backboard for scooping a pile of gravel. The door got all sorts of bent-in by over a foot in every panel and in multiple places, but it still worked and the rail hardware stayed for the replacement door.