Tip N' Roll bleachers are perfect for indoor/outdoor auxiliary seating requirements. Unit easily tips up on its casters for convenient storage. Frames are 100% welded aluminum angle Seat planks are annodized aluminum High grade swivel casters & rubber foot pads will not mar your floors Due to constantly changing specifications, please check local building and safety codes for compliance. Includes single foot planks WARNING: These lightweight units are easily tipped up for rolling by any responsible adult. However, if tipped up outdoors, extreme caution should be taken in windy conditions. Multiple adults may be required to control the unit.