Red PTFE/White silicone septa + Black cap without hole, for 4ml screw top vial SV104CS 15x45mm vials have a 13-425 GPI thread and can hold up to 4ml of sample. Use the 13 x 425 caps with septa for use as sample vials and with diffusion caps for wash vials. With closed top screw seals, these vials can also be used as storage vials.