He's 20 lb, but I bought the larger size to give him plenty of room. It was ridiculously easy to assemble, although the instructions said nothing about the assembly that goes onto the axle before the rear wheels go on that engages with the brakes. I kind of wonder if not knowing what to do with that part is the reason some people think the wheels are wobbly, because I don't find them wobbly at all. It's very sturdy, nice looking, and folds easily. It fits in the trunk of my 2006 Honda Accord even along with the large plastic box I use to hold my jumper cables and such, a couple of rolled up yoga mats, and a memory foam seat cushion. It's a tight fit, but it does. Implied by this is the fact that it is light enough to lift into said trunk. The only thing I don't like, and I'm not taking off a star for that, is that the two tethers are not actually attached to the frame. They seem to be attached to a board or something that sits under the dog basket part. I also don't think a whole lot of the cup holder or its attachment. Unless I were very very careful with it I think it well might break off. Solved that by just not using it.