Style A refers to a case with an upper section (lid) attached to the lower section (base) with a full-length piano-type hinge.  The lid angles back when opened to slightly more than vertical which avoids accidental closure when loading or unloading case contents.  Webbed strapping is used to support case lid in an upright position when opened.  Opposite the full-length piano-type hinge is a mechanical catch(es) for securing the case closed while in transit.  A hinged lid style A case has an upper (lid) section which is generally smaller than its lower section (base).  Style A cases are ideally suited for components that have a handle on top and can be easily loaded and unloaded by one person (items such as electronic instruments video and multimedia devices LCD projectors laptop notebook tower & desktop computers and other similar size & weight devices.