There are different types of backpacks or knapsacks offering various functions and features, but all of them can be worn on the back with straps around the shoulders. These have the advantages of leaving the hands free and spreading the weight across the shoulders so that the entire weight is not supported by one side only. This is ideal for heavy loads such as those carried by hikers or mountaineers. Features such as padded straps that fasten around the top of the hips and metal frames give more support. Having the hands and arms free suits most people, such as rock climbers or those with small children.
Travellers and holiday-makers find travel backpacks useful, particularly those with wheels that can be used as rolling backpacks. Wheeled luggage is popular as it puts less strain on the person carrying the luggage but it can't be wheeled up flights of stairs so a bag that converts into a backpack gets around this problem.
Rucksacks are more comfortable to carry than handheld suitcases. Some backpacks are designed with a small handle so they can be carried by hand if required. Some travel rucksacks come with detachable daypacks. A daypack is smaller version of a rucksack which can be used to carry round a few items required for a short trip.
One issue for both adults and children is backpack safety - it is important to use your backpack correctly to avoid causing long-term back problems. Children who are still growing are more vulnerable to spine damage caused by twisting their backs out of shape under heavy burdens. School children find rucksacks useful for carrying school equipment and trendy backpack bags which suit young people are available. These need to fit correctly so see School Backpacks for advice on sizing. Parents of young babies may like to consider carrying their infant in a baby backpack designed to hold your baby securely while you are out and about.
With the bewildering array of bags, knapsacks and backpacks on the market it can be hard to know which one to choose. Look at the section on Backpack Bags for advice on what to look for when buying a backpack. The section on Rucksacks and Daypacks discusses how to care for your backpack, how to pack it correctly and how to select one suitable for a particular activity such as camping. Sizes range from enormous rucksacks with over 5,000 cubic inches capacity to fashionable and stylish backpack purses and handbags.