Day/Night Solar Vent 4" - WhiteThe design threads into included deck plate, and is removable from the outside without tools. On/off fan switches, LED lights, and intake/exhaust switches are accessible from inside the cabin for ease of use.Features: Circulates fresh air in the boat cabin eliminating mold, mildew, and musty air Moves 1,000 cubic feet of air/hour or 24,000 cubic feet of air/day (4" model) A rechargeable battery allows for 24-hour continuous operation Whisper quiet fan operation No wiring required Built-in on/off fan switch, LED lights, and intake/exhaust switch High capacity NiMh battery operates vent for up to 24 hours without sunlight on a full charge Threads into included deck plate and can be removed from outside without tools Complete air and green water shut-off from below All Day/Night Plus models come complete with a white plastic interior trim ring, insect screen, mounting hardware, and an easy-to-understand installation manual Replaces NICRO 3" and 4" snap-in deck plates (fits existing holes once snap-in deck plates are removed) and Day/Night Plus, models Owner&';s Manual (pdf)Brochure (pdf)