The most versatile and reliable coaxial system available for various NMR experiments. General applications include small volume NMR, external referencing or locking and magnetic susceptibility determination. Ideal for variable temperature studies, all parts are made from Pyrex glass. Note: Outer tube must be ordered separately based on magnetic field strength. Note: This product is only compatible to be used with Wilmad-LabGlass 7 inch Precision NMR Sample tubes 506-PP to 542-PP