Trekking backpacks are specialized bags designed for outdoor activities like hiking and camping. They come in various sizes, typically ranging from 30 to 70 liters, allowing users to carry essential gear, food, and water. Features often include padded shoulder straps, hip belts, and multiple compartments for organization. These backpacks are made from durable, weather-resistant materials to withstand harsh conditions. Many models also have hydration reservoir sleeves, allowing easy access to water while on the move. Popular brands include Osprey, Deuter, and Gregory, known for their comfort and functionality in outdoor adventures.