3100D series extra heavy duty aluminium straight ladder. Meets or exceeds CSA Grade 1A, ANSI Type 1A. Heavy duty “I” beam construction, 3 1/16 x 1-1/4 inch rails provide stability, torque resistance and high strength to weight ratio. Heavy duty serrated “D” rungs prevent slipping for safe and sure climbing. Yellow ABS, high impact non-marring end caps.