This safety ladder is mounted on four spring-loaded casters. When weight is applied, the casters retract, compressing the rubber-footed legs to the floor for secure footing. Tubular steel and cross bracing provide a safety ladder that will last for decades. These are rugged ladders built to take a beating. Meets OSHA requirements. Some assembly required. Height at top step is 19" for the 2-step ladder and 28½" for the 3-step ladder.