Greg got the box custom made... not sure where he finally got it from, I gave up are searching for days, we just couldnt find what we wanted. So custom made it was. We havent decided what we will do with the space where spare wheel was but the wire mesh for more storage crossed our minds. The box has 2 vents one each side. The mods have been weighed and rated so all is good for genie and fuel plus tools etc, Also means our gas bottles can be stored securely while on our driveway instead of having to lug them into garage. All up we are very pleased. Absolute Caravans in Balcatta ( for WA forum members)did the mods for us but it did cost a bit.