Booyah Medium Dog Stroller & Pet Bike Trailer with Suspension - Blue Comes with everything to use as a stroller and a trailer. Not an optional purchase like the competition. Don't forget to get the handlebar cup holder/organizer sold separately. Item number B00CZ2NYN6. See optional cargo rack sold separately. Suspension and 12 inch front swivel wheel. Pneumatic wheels. Not plastic. Bike hitch method and NOT clamp method which can bend frame and wear bike paint Size: Medium up to 60 lbs tow capacity but please see that your can fit within the interior dimensions. 40lbs dog seem to be the max size to fit. Instructions appear to be missing. Please look for instructions under the cushion.