1.5 oz/sq ft, 12" Wide, 0.045" Thick - Build Quick Thickness for Parts Chopped Strand Mat (also known as fiberglass mat) has short strands of fibers held together with a resin binder. The fibers are randomly oriented. When resin is added to the mat, the binder dissolves and the fibers can be moved around. It is easier to conform mat to tight curves and corners than it is with weaved fabric. Chopped Strand Mat is the least expensive fiberglass and most frequently used to quickly build thickness for parts and between layers of fabric for building molds. It can be used alone or in conjunction with fiberglass fabrics, or woven roving in larger fabrications and to build strength. Fabricators generally tear apart Chopped Strand Mat, rather than cut it. This maintains the length of fibers along the torn edge, which create stronger bonds with subsequent layers