Frison's KO2 mask is a functional mask with a built-in oxygen supply pouch that can provide 20 minutes of oxygen in emergency situations. Since the pandemic, masks have become an important commodity in our daily lives, and their uses and functions continue to develop. Frison's KO2 mask works effectively when oxygen is scarce in a space where large crowds gather. It can measure oxygen saturation and pulse rate as well as supply of oxygen, and this data can be transmitted to smartphones through NFC technology. The KO2 mask requires many components to fulfill its various functions, and Defining was able to design the components while simultaneously realizing a seamless design that looks as if the components were not built in.