Chrominex volatile organic analysis vials with septa and screw cap 40mL 24-400 Clear Screw Top EPA VOA Vial, Black Closed-Top Cap Screw closure Clear borosilicate glass and Black PP cap material PTFE/Silicone septa Closed cap Ideal for water sample collection for volatile organic analysis Vial shoulder slop designed to minimize air bubble entrapment Certified to meet or exceed EPA