High temperature 5 MHz probe for measuring up to 400 inches of steel at 1 ° F and up to 5 inches at lower temperatures. The measurement range depends on temperature 040.5 to 68 inches at 0 ° F (125 to 20 millimeters at 1 ° C) 05.1 to 400 inches at 0 ° F (3.25 to 4.204 millimeters at 1 ° C) -4 to 400 ° F (-20 to 204 ° C) operating temperature 0.5 inch (12.7 mm) contact diameter Need separate