How do you change the battery of a catch-a-beast?

Turn device over so that the belt clip is facing you and the winder is now on the left.

You will notice a recessed button to the centre and right of the belt clip. Depress this button firmly with an thin instrument (I used a jeweler's screwdriver but a ballpoint pen should suffice) while pulling/pushing belt clip to the left over top of winding handle.

The recess for the two AAA batteries can be accessed. Replacement procedure of belt clip cover is reverse of its removal.