Canon A-1 - Manual (Page 21)

Eyecup 4S
This is an accessory eyecup which snaps into
the eyepiece grooves. Its use is not
mandatory, but viewing with it may be more
comfortable,^ and it helps block extraneous
light from entering the viewfinder.
Action Grip
The A-1 has a handy, built-in finger grip, but
to make camera holding all the easier, it
comes with a detachable action grip as well.
Before attaching the grip, load the battery
into the camera. Then, using a coin, screw
the grip into the action grip mounting socket
guided by the positioning pin on the front of
the camera body.