Material: Opalite Glass. Opalite is a trade name for a man-made opalescent glass. Each plug slightly varies in color, but typically a cloudy white/clear color is produced.
Double flared
Available in sizes 6.5mm to 25mm. A quick way to measure teardrop shaped plugs is to measure them top to bottom and side to side. Add the numbers up, divide by 2 and you have the gauge size.