Making AE number card window

[RotoTech99]

A 1-1/2" prescription pill bottle cap can be used to make a outline
for AE number card windows by tracing around its edge
with a fine point marker, then cutting out carefully around
the outline.

Make the small alignment notch with a small clipper. If you can't
make the slot on the upper left side, you can trim the edge at
that spot so that it rests under the card holder edge, but allow
a screwdriver tip to go under to work the card holder latch
to lock or release the card holder.

The plastic from a package that has a clear plastic portion such
as a pack for labels is good for creating the window as long as it
is more than 1-1/2" in size.