WGS 72" Arborite Straight Edge For Glass Cutting are manufactured from a dimensionally stable solid slab material. The Arborite material has a black melamine core with a smooth outside aluminum oxide cladding layer. The outside cladding layer is high pressure laminated to the both sides of the core for permanent adhesion. The cladding will not scratch the glass and its surface is so dense and hard that marring of the surface can only be achieved by scratching with a diamond scribe. These Straight Edges have a cut out hole on one end so that the unit can be hung for storage. Thickness: 1/2" - Width: 3" - Length: 72".