The high-permeable pressure relief valve technology of Mi 11 Ultra has nothing to do with the “valve”. Its realization principle is a semi-permeable membrane. The material of this semi-permeable membrane is ePTFE. When the water pressure increases, external air can squeeze in through the small holes on the membrane surface, while liquid water molecules cannot penetrate this layer of ePTFE due to surface tension. Holey. When the water pressure suddenly decreases, the internal gas will be discharged in time, so that the pressure inside and outside the phone is as the same as possible. However, this technology is more of a publicity stunt, and the water resistance of the Mi 11 Ultra has no advantage in the IP68 dust-proof and waterproof model. IP68 dustproof and waterproof requirements are the minimum standard, which can be kept for 30 minutes without water in 1m of water. The standard of Xiaomi Mi 11 is that it can keep water in 1.5m of water for 30 minutes, which is not as good as the 2018 iPhone Xs. In 2018, the iPhone upgraded IP67 dust and water resistance to IP68 for the first time. That year, iPhone Xs and iPhone Xs did not enter water for 30 minutes in a depth of 2m, which is higher than the standard of Xiaomi 11 Ultra. For the 2019 iPhone 11 series, it has been upgraded to keep water out of water for 30 minutes in a water depth of 4m. The iPhone 12 series in 2020 has even been upgraded to a water depth of 6m for 30 minutes without water. In terms of data, Xiaomi 11 Ultra has no advantage. However, in view of the fact that mobile phone manufacturers currently support IP68 dust and water resistance, accidental water ingress will not be guaranteed. In addition, Xiaomi 11 Ultar is the first mobile phone to support dust and water resistance, this time it is worthy of recognition.