The D1320-2 Aluminum 20 ft. Extension Ladder has a duty rating of 250 pounds and heavy duty modified I-beam side rails. The TRACTION-TRED D rungs are slip resistant and the side rails are interlocking. Heavy duty spring-loaded locks operate smoothly. Durable shoes rest flat or are held in spur position with SHU-LOK feature. Mar-resistant end caps help protect the surface ladder is leaning against. Exclusive ALFLO rung joint means TWIST-PROOF performance every time.