The tower chassis housing is made of sturdy steel and protects the internal components from damage. The front panel of the chassis may be steel or strong plastic. The internal components are mounted onto the chassis base, within the computer. Usually, the removal of retention screws on the back panel allow the front and top panels to be slid off of the base, revealing these components. In some older models, the chassis is hinged at the back, so that by depressing buttons on the sides of the housing, one may lift the top panel open.
