U. S. Concrete Products can supply cast iron or steel gratings.  Grates can be round, rectangular or square.  The style may vary depending on the application.  Cast Iron gratings are available in  heavy duty for traffic loads, medium duty for  driveways and parking lots, and light duty for non-vehicular traffic.

Steel gratings are manufactured of A-36 steel and conform to ASTM  A569 specifications. They are available in H-25, H-20, H-15 and non-traffic loadings.  Gratings can be galvanized or painted to customer specifications.
http://www.usffab.com/usffab-products/catalog/details/9

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