The VWR Scientific 125 mL Polycarbonate Erlenmeyer Shaker Flask with DuoCap, CAT #89095-258, are nonpyrogenic and ideal for culture, storage, media preparation, molecular biology and related applications. Sterile. The unique DuoCAP cap is a vented cap with a 0.22um pore-size PTFE membrane for aerobic (sterile air exchange) or anaerobic (no air transfer) applications. These caps allow aerobic and anaerobic cultures to be performed in the same flask without changing the cap. Flasks and DuoCAP caps are autoclavable and sterility tested to SAL 10-6.