There are two types of fiber optic splice closures: Inline Closure and dome fiber closure. Ordinary fiber optic splice closures include pipe fiber optic cables. The horizontal type is more choice because it is more convenient to install and fix, but it will directly eroded to the fiber core after seepage (water vapor). ADSS and OPGW cable Generally, there are more cap types. Although the installation is complicated, the leakage prevention performance is good. Even if water vapor enters the fiber optic splice closure, there will be water at the bottom of the fiber optic splice closure, which generally has a low probability of affecting the fiber core. Especially in the southern regions where there is more rain and the air is humid, caps are preferred. The function of the fiber optic splice closure is to protect the optical fiber and optical fiber connector from vibration, stamping, bending, etc. and prevent moisture. Therefore, the fiber optic splice closure should have the following properties: 1. Good sealing. The transmission loss of optical fiber is closely related to the waterproof performance. Therefore, the fiber optic splice closure must have good air-tightness and waterproof performance. Generally, it is required to effectively waterproof, prevent moisture, and prevent the intrusion of harmful gases within 20 years. 2. Better mechanical properties. The fiber optic splice closure must have a certain mechanical strength to ensure that the pressure exerted by the optical cable connection reaches 70% of its strength, and the optical fiber performance therein is not affected. 3. Long-term corrosion resistance. At present, the outer shell of most fiber optic splice closures uses plastic products. In addition to corrosion resistance, the aging resistance and insulation properties of the materials should meet the 20-year life expectancy. 4. The splice box should be easily removable and the material can be reused. 5. fiber optic splice closures should be as light as possible to reduce the labor intensity at the time of connection and shorten the operation time.