Hey Dead! Looking back a bit on the Revolution thread I saw that we were also recommending mouthpiece tips as a suitable plug for the window on the Rev. Omicron sells them in 5 packs ( http://www.delta9vapes.com/products.php?product=Clear-Silicon-Tips-6-piece ) and I -think- this would work as well at a quarter a piece ( http://www.apolloecigs.com/product-p/atestercondom.htm ) Good luck!