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A messenger bag (also called a courier bag) is a type of sack, usually made out of some kind of cloth (natural or synthetic), that is worn over one shoulder with a strap that goes across the chest resting the bag on the lower back. While messenger bags are sometimes used by couriers, they are now also an urban fashion icon. Some types of messenger bags are called carryalls. A smaller version is often called a sling bag.
This design of bag has been used in the transportation of mail and goods by numerous types of messengers, including Pony Express riders, postal workers, messengers on foot (especially in ancient times), and bicycle couriers. Some Royal Mail carriers in the United Kingdom currently use large messenger bags to deliver mail in lieu of a Postbag.
The design of the modern messenger bag traces its origin to the utility lineman's bag of the 1950s made by De Martini Globe Canvas Company, which was founded by Frank De Martini and run with his two daughters, Kathleen and Marge. The bags originally allowed lineman to carry necessary tools within easy reach while climbing utility poles.
De Martini messenger bags were made of cotton canvas with a waterproof lining, a cotton webbed shoulder strap and two closure straps. Bags had one small internal pocket for invoice slips. De Martini Globe Canvas messenger bags originally bore no manufacturer's label, and were sold only to, and issued by, New York City messenger services, and not sold in stores. Globe Canvas supplied bags for most New York messenger firms through the 1970s and 1980s. The larger messenger firms issued riders bags in exchange for a deposit. Bags were color-coded by firm, with the two largest companies, Mobile Messenger and Can-Carriers, using red and blue bags, respectively.
In 1984 John Peters redesigned the De Martini bag using Cordura nylon, delrin buckles and reflective stripes and finished the bags with (industry first) cordura edge binding and hence set the stage for the messenger bag craze. His designs are now the industry standard for all modern messenger bags.
Pre-dating today's messenger bags described herein as specifically for bicycle messengers, fashion brands had been creating "messenger style" bags modelled after military map case bags and document pouches featuring a shoulder strap intended for wear across the chest for over a century.
Similar in function to backpacks, messenger bags ensure comfort to people carrying heavy and/or bulky items, while allowing easy access to the contents.
Messenger bags typically incorporate features that make them particularly suitable for cycling, such as fittings that make it easy to adjust the shoulder strap, quick release buckles, an adjustable hinged buckle, and the ability to attach a variety of accessories, such as lights, phone holsters, or U-locks. Contemporary stabilizing straps help to prevent the bag from shifting while riding. The top-opening one-strap design allows messenger bags to be easily swung around front so that their contents can be accessed without having to remove the bag.
Messenger bags are often used as a fashion accessory. While they can be found in the possession of either gender, they are often commonly employed by men in a function analogous to a woman's purse (that is, to carry bulky items that do not fit into pockets, or a large number of items, while doubling as a fashion accessory). Messenger bags have also become fashionable in urban environments, among cyclists and commuters. Many college and high-school students make use of them for fashionable and functional purposes, especially those who commute on bicycles. Companies such as Mobile Edge among others, design messenger bags specifically for the collegiate market. Compared to a backpack, it is much easier to place and remove text-books, notebooks, essays and supplies from a messenger bag because they can be easily shifted to lie on the side of the body (or, if the strap is long enough, it will be there by default), granting the wearer better accessibility. Messenger bags also provide more weather resistance than traditional leather satchel-style school bags.
Materials used in messenger bags are often more durable and water-resistant than other over-the-shoulder bags. Contemporary bags use thicker gauges of canvas and tarp shielding for the inner waterproof lining. The most popular materials used for the construction of a messenger bag's outer shell are Cordura 1000 Super Durable Water Resistant Nylon By Invista and ballistic nylon. Other materials include vinyl waterproof tarp lining used to make the messenger bag waterproof. The liner also provides the support structure for the messenger bag; this keeps the bag from falling over on itself. Some companies eschew the standard PVC waterproof lining for compounds such as thermoplastic polyurethanes, which are newer, comparatively more expensive, more durable, more environmentally friendly, and less volatile.
To read more about messenger sling bags, please click on the following link: http://en.wikipedia.org/wiki/Messenger_bag