I had this box made exactly for the 15" Memphis m3's a year ago. It is built to memphis specifications an is tuned to 35hz. has 3/4 mdf board for bottomand sides an top has 7 layers of fiberglass.Box has a diamond port on the side so big u can stick your head in it.got well over $500 in box for materials paint claearcoat an labor looking to get around $300 for the box. Prefer local pick up but will ship or deliver with 200 miles for an extra hundred dollars.