NORELL 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, for auto-sampling systems or high throughput NMR. Redesigned from the ground up and with emphasis on quality and precision, Norell has succeeded in virtually eliminating tube wall and bottom variation. It is not recommended to fuse this glass with standard vacuum manifolds and like, since they are generally made of Type 1 Class A glass.