A Mini Splice Protection Box, also known as a heat shrinkable tube box or FTTH drop splice closure, is an indoor device used to protect fiber optic splices. They often include a splitter for signal distribution. Fiber Distribution Hub (FDH): FDH closures are used in fiber-to-the-home (FTTH) networks to. Buy high quality Fibre Optic Drop Cable Protection Box from FS. Fiber distribution box is suitable for the wiring connection of optical cable and optical communication equipment, through the adapter in the wiring box, the optical jumper leads the optical signal, and realizes the optical wiring function. It could be indoor or outdoor use, with good waterproof capacity. To ensure consistent performance and longevity, it is essential to adhere to strict technical specifications.