The Louisville Everest Series aluminum attic ladders have a working load capability of 350 Lb. They feature a tri-fold design with heavy-duty aluminum steps and stiles. The double-riveted construction provides added stability and security. The adjustable stile and pivotal floor pad make installation and lighter weight, easy-to-use design. Rust-resistant. Fully assembled and ready-to-install with instructions. Full width piano hinge across the frame at the head of the stairs. The springs expand uniformly under load and are hand tool adjustable for safety and reliability.