Spring-mounted wheels retract when the stool is stepped on. Steel construction with non-slip strips, protective bumper around the base. Spring-mounted wheels retract when the stool is stepped on. Steel construction with non-slip vinyl strips and protective bumper around the base. Ships in two pieces and requires no tools for assembly. Global Product Type: Step Stools-Step Stool; Number of steps: N/A; Stools Type: Rolling Stool; Maximum load capacity: 500 lb.