Top Diameter: 1-4/5 inch (46mm)
Bottom Diameter: 1-1/2 inch (38mm)
BPA-free, made out of Food Grade materials. Provides an air-tight seal to carboys, necessary for proper fermentation. They come with molded hole.
Each has a perfect consistency as they are all injection molded.
The quality is comparable to silicone stoppers. They stick perfectly to Glass and PET, even when they are wet, however, to improve the seal between glass carboys and the stoppers is best if both are dry.