Flexible Binocular Lens Cover

I made it to spec for Nikon binoculars' peep holes. They should be able to fit other brands and even the front lenses by scaling them to what you would need.

They're made to stay on using the tension through the connection between the two caps and the grippy texture of the binoculars. Put them on with the binoculars completely closed and the open them a bit so there's a little bit of tension.