A cap sleeve is a specific style of short sleeve that hangs over the edge of the shoulder without extending along the underside of the arm. It is cut and seamed to fit on the shoulder and taper to nothing underneath the arm. This style is usually not as loose as a standard short sleeve T-shirt, but more like a small umbrella — or cap — covering the shoulder. Cap sleeves are often used for ladies fashion tees and dresses. They can create the illusion of a wider shoulder span, which can balance the width of the hips. However, they can also cut the arm and make it look larger than it really is, so they may not be flattering for everyone.