Menus are sometimes hierarchically organized, allowing navigation through different levels of the menu structure. Selecting a menu entry with an arrow will expand it, showing a second menu (the sub-menu) with options related to the selected entry.
Torsion springs are normally mounted horizontally above the opening of your garage door. When you pull the door down, cables attached to the bottom corners actually force the springs to wind up, in turn energizing the system.
The spring loaded hinges work well, however can break or snap with age, causing them to potential damage your door frame or bystanders. Hydraulic Hinges. The more expensive type of self closing door hinges use hydraulic pressure to close the door.