Step Calibration Block, Product Type Step Calibration Block, Compatible with Manufacturer Model Number R7900, R7920, TM-8811, Compatible Product Type Ultrasonic Thickness Gauge, Includes Carrying Case, Steel Thickness - Maximum 0.75 in, Steel Thickness - Minimum 0.100 in, Overall Diameter 0.75 in, Calibration Certificate Type NIST, Overall Height Not Applicable, Overall Length Not Applicable, Overall Width Not Applicable, Manufacturer Warranty Length 1 yr