This is a replacement housing for a Merlin M842 garage door remote.
Additional required materials:
2x Rubber buttons (salvageable from a calculator). The kind with conductive pad on the bottom
2x Screws, 3x10 will do.
There is a version of the housing with just the center holes for the buttons for you to modify to suit dimensions for the button you have available.
More details about the build on my blog