Very good construction. It is very good in its operation, both in pushing and pulling. It has user-friendly and well-made supports and handles, both for hands and for ropes, straps, etc. The friction surfaces under the two wheels are thick plastic sheets, which are effective for both carpet and concrete floors. I believe that the durability of these plastic sheets will show over time. Of course, in the worst case scenario, it will "run" on the metal rails!