During use there is a risk that a male connector for a guide wire is bent. 5 to 10, preferably 1 to 4; that comprise about 1 to 50%, preferably 5 to 15% of the weight of the filter media; that have a specific gravity of 0. A specific example of a cyclic ether group is an alkylene oxide, such as an oxetane group, substituted with one or more fluorinated alkyl groups. In addition, the AlGaN layer can be devoid of carbon throughout. The present invention has simple structure and good insulativity, and has stable electric connection when being connected with a temperature sensor plug, so that the temperature sensor works stably.