Straight Ladder, Overall Height 12 ft., Overall Width 18-1/8 In., Material Aluminum, Load Capacity 300 lb., Ladder Height 12 ft., Number of Rungs 12, Top to Bottom Rung 11 ft., Rung Dia. 1-3/4 In., Rung Spacing 12 In., Rung Width 1-3/4 In., Tread Deep Serrations, Tread Depth 3/4 In.Standards ANSI A14.5 (2007), OSHA Straight and Manhole LaddersLadders have the exclusive ALFLO rung joint connection for Twist-Proof performance and increased rigidity. Rung joint connection is 5 times stronger than ANSI code requirements. Combination shoes with slip-resistant rubber pads for hard surfaces or swivel the shoe to use the spur plates for penetrable surfaces.Type IA300-lb. Duty Rating Type IAA375-lb. Duty Rating