Canon A-1 - Manual (Page 22)

Semi-hard Case
To protect the camera, particularly when
carrying it, insert it into its semi-hard case.
The screw in the bottom of the case screws
into the camera’s tripod socket. You can
easily shoot pictures even with the camera in
the semi-hard case by turning the top cover
down. If you wish to remove the top cover,
turn it down, slide it straight up in the
direction of the arrow and pull it out as
indicated in the photo. To replace the
cover, insert its hook into the corresponding
hole on the case and pull it straight down.
For closing the top cover, the lens’ focusing
ring should be turned to infinity (oo).