Between the outer and inner cabinet, there's a heat insulation (thickness of 18mm), which is made of high temperature resistant, low heat transmit foam material to prevent heat, burn and shake. That's where the IP68 fiber distribution box comes in β a specialized protective enclosure designed to ensure that fiber connections remain stable and efficient for 10 years or longer, even in the harshest conditions. It typically contains splice trays, adapters, and cable routing components to manage fiber connections. The material should be impervious to water, dust, and other environmental factors.