HPLC LC 8-425 Screw Thread Vial Caps, 8 mm, PTFE/Silicone Septa, Black, Polypropylene, 100 pcs/pk B07DFCMTQV. $47.90 $23.99. Color: black Features: Screw Thread Top 8 mm. Suitable for 1.5 mL, 1.8 mL, 2 mL 8-425 vials. Black screw cap with hole + PTFE / Silicone septa Compatible with most Autosampler vials.