Bezel kits incorporate moulded corner pieces that will fit at any depth within the case, and utilise extruded aluminium for the bezel sides.
These aluminium sides screw directly to the side of the case and rubber o-rings keep the unit watertight. Your panel is screwed directly to the bezel. This offers greater flexibility for placement in the case, and much better durability. Bezel mounts can be used to house electronics or test and measurement equipment within the case.
Please note that the installation of bezel kits is a complex job that should only be undertaken by experienced professionals.