Waterproof relay fuse box with a sealed housing protects relay and fuse terminals from moisture, dirt, and vibration in demanding environments. 4pin or 5pin relay socket: standard automotive relay socket, compatible with either 4pin or 5pin relays depending on model. 12V or 24V system ready: supports both 12V and 24V automotive electrical systems for flexible use in cars, trucks, RVs, or off road vehicles. Blade fuse compatibility: accepts standard ATO/ATC blade fuses to provide overcurrent protection for auxiliary lights, audio, engine, or custom electronics. Use scenarios Off road or rugged work vehicles need reliable protection for auxiliary lights and accessories in mud, water, and vibration environments. RVs or trucks that operate on either 12V or 24V systems require flexible power distribution for lighting and electronics. Custom electronics or audio installations benefit from standard blade fuse protection to safeguard circuits and components.