4 fold louvers
The name 4 fold louver comes from the bottom front of the louver being folded into four layers of aluminum.
The top of the louver has a double hem to add even more strength.
The louver ends are then wrapped around an aluminum rail system (not wood framing) to complete the vent's strength.
The rail system looks something like this.
Most other vent manufacturers use a track instead.
Smooth trim is our preference, not pie crust.