With the huge influx of COVID-19 patients suffering from serious breathing issues in March/April 2020, hospitals were short on ventilation equipment. Many patients could still breathe autonomously but needed additional oxygen and some overpressure to expand the lungs. In addition, the exhaust needed to be filtered to prevent the spread of COVID-19 viruses within the hospital. An Italian hospital first re-purposed the Decathlon snorkel mask which is readily available and developed the first adapter, named the “Charlotte valve”, to properly connect it to oxygen supply and filters. This valve was difficult to 3D print and had other limitations, so there was demand for an improved design which would be faster and easier to 3D print while also offering different configurations.