The Metro Divider Tote Box line offers safe and efficient storage of items in bulk or compartmentalized models with the use of optional dividers. Metro Totes and accessories are available in any of three different materials to meet the specific needs of today's parts handling requirements. NAT — Refers to natural polypropylene-base resin products. They are impact resistant, durable and have a high chemical resistivity. The standard color for any product ordered with this suffix is gray. CAS — Refers to Bentron, a conductive polypropylene-base material. This material contains a carbon additive to provide an electrically conductive path through the material. Bentron has a surface resistivity of less than 105 ohms/sq. All products with this suffix are black in color. BAS — Refers to Benstat, Metro’s patented static dissipative polypropylene-base material. Benstat has a surface resistivity of more than 105 ohms/sq. and less than1012 ohms/sq. The standard color for any product with this suffix is blue.