You could do one of two things. Take the woofer out, put screws into the inside of the box connecting it to the car. Or you could just use some small "L" brackets, or I also used some small hinges to secure the box to the car. Watch out for where your gast tank is. I'd try to use the screws as close to the opening of the trunk as possible. I heard a guy say he screwed down his box, but way towards the back, like almost against the seats, and he said he made a hole in the tank. Also, just use some small screws. Maybe like 1" ones. It doesn't take much to hold it in place.