This is open box and unused as you can see in the 3rd picture. 

From the manufacturer:

All bilge heaters must be certified for use in environments where flammable vapors may be present, but this is the only one that is also WATERPROOF! The heater utilizes a dual component design. This provides the user with twice the protection of all other heaters on the market, because it has two heating modules, long-life ball bearing fans, and hermetically sealed thermostats. All of this is housed in an anodized aircraft aluminum housing. It is assembled by hand in San Angelo, TX. 

Purchasing any bilge heater other than the TWIN HORNET 45 may be the worst decision you ever make for your boat because ONLY the Twin Hornet is equipped with TWO of every operational component. That's right! There are two thermostats, fans, heating modules and power supplies, all inside one housing. This heater is certified SAFE and meets the U.S. Coast Guard's requirement for operation in an environment where explosive gases may be present. The waterproof thermostats are wired in parallel, so either thermostat will keep the heater operating flawlessly. You cannot buy a safer heating module because they are manufactured with a self-temperature regulating material, making it impossible for them to overheat because of the physical properties of the material. We offer a 3 year warranty, the longest in the industry.