the two halves are held together with super heavy duty draw latches and sealed with weather strip. the finish work with the 1x4s alternate to come together and hide the seam as well. to add to it all i have to do is build a new center section as wide as i want which will probably be 3 feet next time giving the enclosure a total floor area of 7x8. once thats not enough ill mod one side of the center insert and build a ramp for him to be able to go up to the top of the enclosure which will be the same dimensions as the bottom but only about 3 feet high.