a vertical position with the barrel pointed generally toward the ground, a vertical position with the barrel pointed generally upward, or a horizontal position with the barrel pointed generally behind the wearer. Shoulder holsters are typically comfortable for the wearer, as they distribute the weight across the shoulders instead of directly on the belt. Normally, the leather straps cross over on shoulders and back. The spare magazines hang in opposite directions of the body from the holster. It also allows to carry a gun in jacket or sports coat. The direction of this holster is either vertical, for long guns like large or full-frame caliber revolvers, or horizontal, for other firearms. The gun can also be placed over the chest or under the armpit, and the position depends on the gun design. Advantages of this holster are: it is comfortable to wear, even when wearing for a long time; it is easily concealable even with a jacket; a good design usually distributes the weight of the gun evenly. Sling holsters are similar to shoulder holsters, but instead consist of a band worn over one shoulder and another around the chest. This style of holster (designated M3 for the early 1-strap model and M7 for the two-strap model in the U.S. military) was used for pilots, tank operators, and other vehicle drivers in World War II as they were easier to use in the seated position. They became popular with other soldiers who disliked the heavy leather flap on the standard issue M1911A1 hip holster. They are still produced by the U.S. military. The belly band holster is a wide elastic belt with a built-in holster, usually worn under an untucked shirt, to facilitate access. There are various types, worn at the belt line or higher, with the gun placement anywhere from in front to under the armpit. In order to remain in place, a belly band must be extremely tight; this is generally uncomfortable – it is comparable to wearing a girdle. Pocket holsters are used for very small weapons, such as a pocket pistols. Small of back holsters place the weapon directly over the center of the back, allowing for even large handguns to be carried with little printing. While both comfortable and stylish, should the wearer fall onto the weapon (such as in a close quarters fight) serious spinal injury may occur. For this reason, in recent times