Can anyone help with this material?

I'm trying to make it so the sniper glass actually looks like glass and you can see through to the scope metal, but not completely see through like it is. I've tried everything and can't seem to figure it out.

I'm trying to make it so the sniper glass actually looks like glass and you can see through to the scope metal, but not completely see through like it is. I've tried everything and can't seem to figure it out.