Helium-3/Helium-4 Mixture (Dilution Grade) from Mexico
Pre-mixed He-3/He-4 solution at ~3-10% He-3 concentration for dilution refrigerator stills. The isotopic content qualifies under HTS 2845.40.00.00 as enriched helium isotopes. Used directly in cryostats for phase separation cooling.
Duty Rate — Mexico → United States
10%
Rate breakdown
9903.03.0110%Except for products described in headings 9903.03.02–9903.03.11, articles the product of any country, as provided for in subdivision (aa) of U.S. note 2 to this subchapter
Import Tips
• Specify exact molar ratio on invoice; use Dewar shipping with temp monitoring; verify mixture doesn't exceed chemical preparation thresholds