The peculiarity of the UltraBond Seal system is that the screw cap and the liner form an inseparable unit. Through a patented processing technique the molecular structure of the contact areas of the PP Screw Cap and the liner are changed in such a way that without usage of any glue or adhesive the components form a firm unit. Reasons for making such a seal instead of a just assembled cap/liner combination seal could be: • For instruments with very thick and dull needles, in order to avoid the risk of pushing the liner into the vial (9mm UltraBond Seals for Short Thread Vials).