Simple to install

The brackets are key nothing special about the glass, just a rectangle with polished edges.  If you want a size that is different than what is offered, you could just buy the brackets and have your own custom glass shelf made at a glass shop.  Use more brackets if your shelf is longer or you plan on putting a substantial load on the shelf.

Brackets are made for 12 glass, and come with a spacer for the thinner 38 glass.

On minor comment, the glass is not fastened to the brackets and can float around.  This may be an issue in an earthquake or if it is in a position that my get bumped.