国外有一种报警帽，内部安装有微型发射机，当戴帽者路遇歹徒时，只要将帽檐打开，无线电发射器就会发出报警讯号，向警察求救。 日本研制的一种帽子，装有特制的安眠头箍，一按按钮就能产生低频电流，头箍会使大脑控制睡眠的神经松弛，从而达到催眠效果。 科威特气候炎热 Abroad there is a warning cap, the internal installation of a mini transmitter, when the wearer in case of gangsters, as long as the brim opened, the radio transmitter will send a warning signal to the police for help. Japan developed a hat, with a special sleep headband, a button can generate low-frequency current, the headband will make the brain control the relaxation of the nerves of sleep, so as to achieve the hypnotic effect. Kuwait has a hot climate