There are many different types of these carts. The problem is, they sometimes look very similar to each other in style, but differ in important areas like type of wheels, depth of the noseplate, etc. Just check out the variety at this site and you will know what I mean. http://www.handtrucksrus.com/index.aspx?src=Branded&gclid=CPmRgvXlz7gCFZFaMgodO1QAug
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Lots of bassists use a Magna Cart (cute name): I think the popular one is good for 150 pounds, and has 5" wheels. The more expensive one I got has 7" wheels, and is rated for 275 pounds. I'm sure the Magna Cart would be enough for me, but I thought I'd go with a heavier-duty model, and the larger wheels gave me a smooth ride over an uneven brick sidewalk the other week.