Precision-grade (PG) optical breadboards with patented constrained layer modal damping minimize torsional and bending modes to improve dynamic performance. The breadboards include sealed mounting holes which make it easier to contain and clean up spills or retrieve small objects, and incorporate a 3/16-inch steel triple-core interface honeycomb design. Available from 1 x 1 ft up to 3 x 6 ft sizes and 2in and 4in thicknesses, they offer a surface flatness of <±0.004 in. over 2 square feet. Metric or imperial versions can be specified.