Working in film & video production well over 30 years; I've had the opportunity to put most of the 4 wheeled hand truck / conversion carts found in the marketplace, thru their paces. Remin Kart-A-Bag's "Kartmaster HD-500" is simply the best, most solidly designed, Folding, Telescopic & Collapsible cart made! From my experience: Remin Kart-A-Bag's Warranty & Customer Service are second to none! It is great to own true "American Made Quality". - S.H.