Not sure of the dimension; but my granddaughter started using it when she was 2 yrs old. She is now 3 and it's just about too small for her. Really handy on straight walks; but not too stable when there are bumps or curves. Then you are pretty much doing all the work with the stick.
Got this for a 2yr old and just right size, i am sure it is the same as the other colours as in Pink for Girls and Blue for Boys. as the child gets older the handle could do with bieng a bit stronger for the extra weight to push.
As this toy was going to my grandson in Sweden i had it shipped directly there but when i went for a visit it was suitable for a two year old and he is quite a big boy sorry i cant be of help to you as far as dimensions are concerned but what i seen was very good value for money and i was delighted with the quality.