The top joystick shown here uses a square bezel and is fitted with four screws that go through the bezel, the panel, and into holes on the body. The image (lower left) shows the same joystick mounted without a bezel and (lower right) mounted with a round bezel. The bezel’s main function is to align the boot and joystick flange, clamp the boot to form a seal, and improve the installed appearance of the joystick.