数字         **位数字                           第二位数字

              防止异物进入                         防水

 0            没有保护                             没有保护

 1            ＞50mm的异物                        垂直落下的水

 2            ＞12mm的异物                        斜落下的水珠

 3            ＞2.5mm的异物                        雾状水

 4            ＞1.0mm的异物                        飞溅出来的水

 5            防尘                                  喷射出来的水     

 6            尘封                                  海水

 7                                                  部分浸入到水中

 8                                                  完全浸入到水中