ATS offers an extensive line of calibration test blocks world renowned for quality and reliability. Each of our basic designs and styles below are available in English or metric units. ATS ultrasonic reference blocks are available in a wide range of block types and materials including 1018 steel, 7075-T6 aluminum, and 304 stainless. Our quality control program is certified to MIL-I-45208A using instruments per MIL-I-45662A. Each block is certified traceable to NIST, with standard and custom units available. Optional features include a custom logo and additional certifications. Call our experienced engineers to provide a quote for custom diameters, lengths, standard specifications, and materials that will meet your unique ultrasonic (UT) requirements.