Comes with four 3 twin wheel hooded casters with brakes 1year manufacturer warranty on casters lifetime on legs Stack up to 20 cots on dollyNarrow enough to fit through most doorwaysFrame of bendproof powdercoated 18 ga coldformed steel with 10year manufacturer warrantyLegs are made of high impact polypropylene plastic guaranteed for life 1year manufacturer warranty on casters Sturdy enough for use with children up to 80 lbs Cover is made of Texron a nonsag open weave extremely durable fabric that meets the strict California Fire Code 117Laceup cover can be tightened periodically if necessary and carries a 10year manufacturer warrantyNo screws nuts or other small parts