Colmated cork stoppers are natural cork stoppers with their pores (lenticels) filled exclusively with cork powder obtained from the grinding of natural cork stoppers. To fix the powder into the pores, a natural resin- and rubber-based adhesive is used. Nowadays, water-based adhesives are also employed in this process.
 
The main purpose of colmation is to improve both the visual appearance of the stopper and its performance.
 
These stoppers present a very homogeneous visual aspect and good mechanical characteristics.
 
They are available in a wide variety of shapes and sizes, the most common being: 45×24 mm, 38×24 mm, 38×22 mm, and 33×21 mm.