"Waterproof Cooling Fan" degree of protection the International Electrotechnical Commission (IEC) recommended IP ×× grade standards, different installation options, rating is not the same. Specific reference to the following description of the selected. In grade standards, "××" is two digits, the first digit indicates the degree of protection against solid, liquid represents the second level of protection. Solid protection level has seven levels, each represented by 0-6; liquid protection grade nine levels, each represented by 0-8.