covid19 ventilators
https://www.prusaprinters.org/prints/26824-modified-splitter-design-for-ventilator
/www.isinnova.it/easy-covid19/
https://www.prusaprinters.org/prints/26824-modified-splitter-design-for-ventilator
https://www.prusaprinters.org/prints/25808-3d-printed-circuit-splitter-and-flow-restriction-d
https://customsurgical.de/en/free-3d-model-for-customizing-a-virus-protection-mask/