IP is the abbreviation of Ingress Protection Rating (or international protection code), which defines the interface's ability to protect liquid and solid particles. IP is followed by two digits, 1 is the solid protection level, from 0 to 6, representing the protection from large foreign objects to dust respectively; The second is the liquid protection level, ranging from 0 to 8, representing the protection from vertical water drops to bottom pressure respectively. The bigger the number, the stronger the ability. The interpretation of IP67 is to prevent inhalation of dust (prevent contact and prevent dust infiltration as a whole); Prevent short-term soaking (prevent soaking).