Our “Standard Series™” NMR tubes are manufactured out of ASTM Type 1 Class B glass, commonly referred to as N-51A. Applications that are suited for using this type of glass are routine NMR where samples are run under room temperatures with no thermal gradients. It is therefore not recommended to fuse this glass with standard vacuum manifolds and the like, since these are generally made out of Type 1 Class A glass. Each NMR tube is checked for concentricity and camber specifications utilizing the latest computer technology.