I bought 5 inch wheels, casters rated at 1050 lbs. I use them under some large garage cabinets that weigh nearly 500 pounds empty. At 7-1/2 pounds each, these reels are massive. Aluminum with an outer layer of molded polyurethane. wheel axle 1/2 inch diameter; Kingpin - 3/4 inch. I won't load them to the 1050 pound rating, but I can trust them to handle it with ease. However, Revain's packaging was unforgivably bad. The six I ordered were placed in a box along with airtight plastic bags. Nothing held them in place and they slipped, knocking out the packages and breaking through the sides of the box. FedEx ended up packing them in one of their boxes, which arrived a day later with a note on a badly torn Revain bill. Fortunately, they are largely indestructible, otherwise they would be badly damaged. So five stars for the videos. -5 stars for the packaging.