by made in the USA
I had a couple of sets some cheap ones, with no jacking provision Made in the USA= Auto Dolly $149.95 a set of 4 w/12x16" 1500 # ea. capacity & a set my girls bought me a quite a while ago, I no longer have now {went with my old car}, Made in the USA= GoJaks/Zendex set of 4 $940+ @ $469 a pair for the 13" 1550 # ea. capacity, they were great but pricey... there are some others, I've been thinking of buying recently, from OTC Tools Easy Roller Dollies OTC-1580 {no photo} w/locking safety pins 12"wide for $141 each @ $524 for a set of 4, all prices were from Summit Racing, not sure where the OTC's were made... I try not to ever buy Harbor Freight or any other type Chinese made crap, when I can help it, they may have some, USA brands too, I don't go there much any longer... The GoJaks 4"casters were great & rolled really well, jack them up or let them down, but you pay for that convenience & USA made quality too... I guess it really depends on you budget & what type you actually want... Good luck with your choices & project