ABDOS Bio-Reaction tubes are manufactured with high purity virgin Class VI Medical grade polypropylene (PP) conforming to US FDA 21 CFR, free from natural rubber & heavy metal. Bioreaction tubes are convenient and economical option for small scale, high density suspension cell culture and are ideal for biological reaction experiments that require aseptic conditions with free gas exchange. These tubes consist of ultrasonically welded 0.22φm hydrophobic membrane to allow gas exchange. These tubes come with a large unerasable frosting white printed writing area and engraved graduation.