Editing Backpack (section)

===Frameless===
The simplest backpack design is a bag attached to a set of shoulder straps. Such packs are used for general transportation of goods, and have variable capacity. The simplest designs consist of one main pocket. This may be combined with [[webbing]] or [[Rope|cordage]] straps, while more sophisticated models add extra pockets, waist straps, chest straps, padded shoulder straps, padded backs, and sometimes reflective materials for added safety at night. These packs are generally produced inexpensively.

Some outdoor packs, particularly those sold for day hikes, [[ultralight backpacking]] and [[mountaineering]] are sometimes frameless as well.

====Sports====
{{main|Hydration pack}}

Sports and hydration backpacks are smaller with a profile closer to the body, wider straps and can come with water bladders and hip belts for running, cycling or hiking. Running hydration packs are the smallest and lightest, many under {{Convert|2|l|abbr=on}} and most under {{Convert|6|l|abbr=on}}. Compression straps across the top of one's body are common as are hip belts. Cycling hydration packs are {{Convert|6-10|l|abbr=on}} sitting high on the back. Although daypacks are small averaging {{Convert|10-30|l|abbr=on}}, all trekking and hiking hydration packs are generally the largest and heaviest. {{Convert|35-65|l|abbr=on}} and above are common.