Hinge #2, 14 gauge, black powder coated. This one goes between sections 2 and 3, one step up from the #1. It has a slightly bigger offset to position the roller correctly as the door starts bending around the track radius at that height. Powder coat protects against rust and looks better than raw steel. If you're replacing hinges, match the number that's stamped on the old one. Putting a #1 where a #2 should be will throw off the roller position and cause the door to bind.