This Louisville 20 foot aluminum industrial extension ladder has a 300 lb load capacity, rated ANSI Type IA. It is equipped with the MAXLOCK rung lock, custom engineered from a patented, advanced molecular polymer, MAXLOCK is the strongest, toughest, lightest rung lock ever made. This ladder includes the patented QuickLatch RungLock system that provides a simple, intuitive method of securing the fly and base sections of the ladder when extended. This ladder also features outside slide guides, D-shaped rungs fully serrated for a slip resistant surface, mar-resistant rail end caps, rope and pulley, full I-beam for a more stable connection and to prevent twisting, and swivel safety shoes to be used as tread down or in spike position. The Louisville AE2220 aluminum extension ladder meets or exceeds the safety standards set by ANSI, CSA, and OSHA.