The D1220-2 Aluminum 20-foot Extension Ladder has a duty rating of 225 pounds and interlocking side rails. The Traction-Tred D rungs are slip-resistant. Spring-loaded locks operate smoothly for easy operation. 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. Exclusive Alflo rung joint means Twist-Proof performance 1.75-inch slip-resistant Traction-Tred D-rungs Durable extruded rung locks are spring loaded to operate smoothly Mar-resistant end caps Smooth operating pulley with polypropylene rope Heavy-duty modified I-beam side rails Durable shoe rests flat on slip-resistant pad or is held in spur position with SHU-LOK feature