Compatible with Aijiren, Waters, Varian, and Shimadzu Autosampler System; 13-425 Septum Cap assembled, ready to use prevent contamination; Septa hardness Shore A 45° PTFE/Silicone septa are most popular for HPLC applications, and pre-slit septa are easier to pierce with needles. Size: 13 mm Diameter, 1.5 mm thick, Compatible with 4ML Screw