Manufactured from Borosilicate glass Clear vials for general analysis; amber vials for light-sensitive materials. Glass vials for collection of water and soil samples for Volatile Organic Analysis. GPI thread, 24-400 Can be sealed with polypropylene caps and PTFE / silicone septa. Used for volatile organic analysis to collect water samples. Vials processed according to Level 3 are not pre-cleaned and are ready for your own cleaning procedure. Level 3 glass vials and caps meet EPA-recommended guidelines for sample container material component specifications. Includes: Vials are supplied with/without caps with 3 mm (0.125") PTFE/silicone septa. Caps are Packaged separately.