Screw-on Plugs/Gauges/Tunnels L.Blue Acrylic 2 Pieces (1 Pair) (B/10) Acrylic is different then plastic. It is good for more people, and the color doesn't change. Please don't clean with rubbing alcohol. If you need to clean it use peroxide or sea salt, these will do just fine. Also don't over tighten, tight is tight.