not sure what they are called but my friend looking to buy one for her GSD any one put me in right direction or any one  used one?

Do you mean a mobility cart for an injured dog to get them out and about or a persons cart to sit in and be pulled/pushed by their dog?

its for the dog to get out and about his back legs are not good, he is fine in the house.

http://www.doggon-uk.com/products.html  

http://www.dogmobile-online.com/Price%20List.htm
www.k9carts.co.uk
http://www.doggon-uk.com/home.html
http://www.eddieswheels.com/index.html

eddieswheels are one of the best but made in usa, and doggon is also made in usa although have uk agent, eddies wheels also have uk agent, have not used one personally but know some that have and they got on with them great, but the two I mentioned I am told are the stronger of the carts on offer but that is only what I have been told