Mounting this Graflex Sport Viewfiner Mask 9101

I purchased this Graflex Sport Viewfinder Mask 9101 which does not fit into the tubular viewfinder. It is a piece of plastic approximately 3.5"x4". What do I need to properly mount this mask?

How can I mount the plastic on the wire and springs of the sports finder? Just snap it in and nothing else is needed?

Sirius Glass said:

... Just snap it in and nothing else is needed?

Click to expand...

Yes. That's how that piece works on my SuperGraphic.

Wow, I do not need duct tape!

That is what I thought, I do not want the plastic piece to fall out.