Micro-Flat Datums Pvt. Ltd. Manufactures Cast Iron Hollow Box Parallel. Micro-Flat Datums Pvt. Ltd. Is an ISO 9001:2000 certified company. Cast Iron Hollow Box Parallel are extensively used in machine shops for set up and machining operations, building up height of work on machine tables and for mounting work for scribing and inspection. Cast Iron Hollow Box Parallel can be offered as matched pairs on request at extra cost.