Of course this wonderful invention was intended for cats to be able to go outside without "going outside", but small dogs love them also. I would say up to about 15 lbs; it is pretty strong.
It was impossible to get an entire chihuahua body to stay up front in the stroller long enough to get a good picture, but they do love these! What's not to like says the "rodent" crew at my house? The pet is protected, can't escape and a human does all of the work.
These are also neat as the carriage(basket) part is removeable and it all folds up nicely. The
door features 3 strong metal twist closures so no chance of accidental escape due to vibration.
I have seen these on the Internet at 130.00 but now 65.00 at Pet Stuff Resale.