I have received a couple of questions about how to change the strap on the Casio PAG-40. Well, this is not a step by step process but you get the general idea...
The Casio PAG-40.
As you can see the straps are held in place by a couple of screws. Both ends are slotted.
You will need two plain ended screwdrivers to remove the screws.
The screws being removed.
One end of the screw is threaded all the way.
Use a toothpick or other appropriate tool to push out the other end.
As you can see, one end is a long tube which the other end screws into.
The strap removed.
The case with the hole which the screw threads into. The installation process is the opposite.
Hope this helps.