Mine is not a sealed unit, but it sits up ina an area out of the reach of most of the salt water. The make is "Blue Sea Systems" and there is a cover, but vapor can still get inside. All metal is corrosion resistant, brass, stainless, plated heavily, etc. I got it at Boater's World, $20.00 for a six fuse box. I used liquid electrical tape to seal the wiring at the battery end, and coated the positive terminals with a wipe of vaseline. I just get tired of running wire, even though I do it seldomly.