Aijiren Certified Vials, Caps and Septa – Postnova. 6 Screw Top Vials, Caps, Septa and Kits Combine the excellent autosampler handling of a crimp cap profile with the ease of a screw cap. The screw caps and precision fit septa give a secure seal with microvolume inserts. • 2 mL, 12 x 32 mm • 40% larger opening.