Tonneau is about 50"....I had some trouble measuring it without a ladder, (Its up in the rafters in the garage)but it reaches from the box to the end of the tailgate. It's got an aluminum frame that clamps or bolts to the bedsides. it also has some ribs to keep it from sagging in the middle. The cab bolts to the original top bolt holes with the original top bolts. Uses the OEM weatherstripping. The bottom half is open through to the rear. If you want to help me remove the bottom I have, you're welcome to it. What I have is a piece of sheet metal anchored to the floor and to a piece of angle iron right under the half cab, which effectively partitions the front and rear just like a pickup. You could easily do the same thing with a piece of 1/4 plywood. I intend to remove it, just haven't gotten to it because I know there is some sort of sealant between the metal and the floor to keep the water out of the cab that is going to be a pain to clean up...I've also got a Tuffy security console for between the seats that I'm going to remove and sell.