国产免费又色又爽又黄在线观看_娇妻接受3p交换爱调教_色琪琪久久综合_又粗又长进美妇后菊

Common handheld terminal devices include mobile phones, walkie talkies, PDAs, 4G/5G terminals, etc. These types of devices are often used by personnel entering explosive hazardous areas. They are generally of intrinsic safety type IB or IC, and the temperature rise of the power supply battery and the surface resistance value of the non-metallic shell need to be considered.