An extension ladder is a type of ladder that can be adjusted in height by extending or retracting its sections. It typically consists of two or more sections that slide against each other, allowing the user to reach higher places safely. Extension ladders are commonly made of materials like aluminum or fiberglass, making them lightweight yet sturdy. These ladders are often used for tasks such as painting, roof repairs, or accessing tall structures. When using an extension ladder, it is important to follow safety guidelines, including ensuring it is placed on stable ground and maintaining a proper angle for support.