What is the difference between 90% oxygen concentration and 70% oxygen concentration in diffusion oxygen supply?

Hello, the question of whether the oxygen generator is a medical device mainly depends on the purpose and related expected effect. It can be judged according to the following definitions: medical devices refer to instruments, equipment, appliances, in-vitro diagnostic reagents and calibrations, materials and other similar or related items directly or indirectly used in the human body, including the required computer software.