The unique shape of the Ultra Yield flasks and their closure by breathable membranes (AirOtop seals) allows much better aeration than in standard glass flasks and therefore better cell growth with increased protein yield can be achieved. Ultra Yield flasks can be used with a volume of media up to 20% of the flask total volume giving much greater production per run. These enhanced flasks together with BioSilta EnBase media give the ultimate shake flask cultivation solution. Ultra Yield flasks are used extensively in Pharma companies within the USA and Europe (see application note across).