Aijiren’s FTU Glass Vial with Screw Neck always use for Water Analysis, Labs often use FTU Vial to hold samples. There are 20ml and 30ml vials. The flat-bottomed design enables the vial to be stably placed on the storage cabinets and shelves in the laboratory. The FTU only has transparent glass, which can be intuitive. To see the changes of reagents in the vial, you can also choose the vial with a scale with a 10ml mark.