Risers set up quickly and conveniently with an easy to operate locking mechanism that provides increased stability and safety. Each step is 3/4" solid core plywood covered with long wearing pile carpeting and aluminum edging for quietness and slip-resistant protection. Platforms are 3' 6" wide by 6' long with ends tapering to 5'. Tiers are 13 1/2 inches wide and stand 8, 16, and 24 inches high. Use Standard Taper Units for a semi-circle layout or use a combination of Standard (473129 904) and Reverse (473129 914) Taper Units for a straight line layout, or extend layout with Straight End (473130) Risers.