Description Wilmad-LabGlass's NMR Precision Tubes are manufactured from borosilicate glass that meets the requirement of Type 1 Class A glass from ASTM E438. Precision Tube has 3 fold less paramagnetic contamination comparing to the Economy tube, and can be operated safely at temperature up to 230 ¢ªC, and within a temperature step of 120 ¢ªC. Precision tube is rated as hydrolytic class 1, which states that the inner surface is resistant to strong acid and base at ambient temperature. Wilmad-LabGlass is adopting a unique precision shrinking and grinding process to shape the inner surface with maximized filling factor (10% more than Economy tube), and a tight ID and OD tolerance as small as 0.0065 mm. None of our competitors are capable to offer even close products. Each of our individual NMR tubes released into the market has been manufactured in the state-of-art facility in the United States and passed multiple NIST traceable gauge control and optical surface defect checks. Properties MHz Rating: 500 Length (inch): 7 OD (mm): 4.9635 ¡¾ 0.0065 ID (mm): 4.2065 ¡¾ 0.0065 Description: Thin Walled Wall Thickness (mm): 0.38 Concentricity (microns): 25 Camber (microns): 13