In recent years, bi-fold fireplace doors have become the most popular
variety.
The term "Bi-Fold" refers to doors which each fold in the
middle during opening the doors. This is like the operation of some
closet doors. This means that there are actually
four pieces of glass. The advantage of bifold doors is that they
don't stick as far out into the room when they're open.This style has metal strips across the top and bottom of each panel of glass, but no vertical metal strips on the glass. The view of the fire is unobstructed, and sturdy hinge structures are part of the metal highlight areas of the glass panels.
JDoor's
Fireplace Door Selector Page is at:
http://mb-soft.com/juca/info/doors/firedoor.html