The dimensions of the "cabin" on the Medium Trailer are 26" x 17" x 20". When fully assembled, the overall trailer dimensions (including wheels and attachment arm) are 46" x 23" x 28" and it folds down to 27" x 19" x 9". With the stroller conversion kit attached, the full dimensions are 50" x 23" x 39" (the handle is 39" above the ground). The wheels on the cabin are 16" and the wheel on the strolling kit is 12", and it is suitable for pets up to 50 lbs. The trailer weighs 27 lbs and the stroller conversion kit adds 7 lbs.