Alpine 12" 1242D box

[dannygp]

I know you love this stuff stu, and I would be greatly appreciative if you or someone could do this for me

Running:
Alpine MRP-M500 500W RMS (1000W Max) Amplifier with
Alpine SWR-1242D 1500W Type R 12" subwoofer

Just need to know size of box so I can get building ready for false floor and new amp next week

Merci

Edit: This wouldn't work properly under a floor would it?

http://www.caraudiodirect.co.uk/alpine-rs12v.html