Navships Calibration Test Block (Inch Version) Used for distance amplitude correction, sensitivity levels and flaw depth information. MTDs are engraved near both scan edges on one face. In accordance with MIL-STD-271G Figure 9, and NAVSHIPS Specification 0900-006-3010/Section 6. Also known as a "Mare Island block. Geometry: Contains six 3/64" diameter side-drilled through-holes at distances of .25" to 2.75" in .25" increments. MTDs are engraved near both scan edges on one face. Dimensions: 12.000" x 3.000" x 1.250".

Navships Calibration Test Block (Metric Version) Used for distance amplitude correction, sensitivity levels and flaw depth information. MTDs are engraved near both scan edges on one face. In accordance with MIL-STD-271G Figure 9, and NAVSHIPS Specification 0900-006-3010/Section 6. Also known as a "Mare Island block. Geometry: Contains six 1.2mm diameter side-drilled through-holes at distances of 6.25mm to 68.75mm in 6.25mm increments. Dimensions: 30mm x 75mm x 300mm