In recent years, twin doors (or cabinet doors) have been less popular
than the bi-fold door alternative.
The term "Twin Door" refers to doors which each swing out
like kitchen cabinet doors during opening the doors. This means that
there are only two pieces of glass.This style has a metal frame that surrounds each glass panel.
JDoor's
Fireplace Door Selector Page is at:
http://mb-soft.com/juca/info/doors/firedoor.html