High Performance 2 1/2″ x 4 1/4″ Testcard for Metal Detectors and X-Ray Machines. Color coded in Ferrous (Red), Non-Ferrous (Green) and Stainless Steel (316) (Blue). Constructed from Heavy Duty (10mil) laminated material in sizes up to 4.0mm, USDA & FDA approved. All products include complimentary certificates of conformity. Need something larger than 4.0mm? Take a look at our thermoform cards.