This Featherlite 40 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, and swivel safety shoes. The Featherlite 4240D aluminum extension ladder meets or exceeds the safety standards set by ANSI, CSA, and OSHA.