The FLAC metal shelf brackets are adjustable to work with nearly any material shelf ranging anywhere from 1/4 n. to 5/16 in. thick. When paired with a shelf measuring 6 in. or less in depth, these brackets can support up to 33 lbs. BLOC is made of i.e. cast zinc alloy. One of our smaller brackets, the BLOC is a great compliment with glass shelves for a minimalist look and feel. When used with wooden shelves or other opaque material, however, FLAC's small size helps to give the appearance of "floating shelves." The FLAC metal shelf bracket set comes with 2 in a package so only 1 package is needed per shelf. Color: Stainless Look.