These vials incorporate the unique Step Vial design that precisely centers a limited volume insert in the neck of the vial. Vial,screw,4ml,clr,WrtOn,100PK. Aijiren Technologies. Compare this item. Vial Dilution 4ml In Lab File, ... Wheaton Sample Vials, 4mL or 0.14oz, Amber, 13-425 Finish with 14B Rubber Liner, ...