VOA Vials CLASS 2: (Precleaned) Generally used for volatile organic compound analysis and sample storage, our 20mL, 40mL, and 60mL VOA vials are available in clear or amber borosilicate glass with a choice of .125" or .100" PTFE/Silicone septa. CLASS 2: (Precleaned) Containers are processed according to EPA recommended wash procedures.