For the purist, seekers of clarity. Made from fully tempered soda lime glass, the KeepCup Brew Cork Edition features a natural cork band. Made in Portugal using waste product from the wine cork manufacture, the band is beautiful to hold. Over time it’s patina will tell the story of your use. We recommend that you do not remove the band, even for washing. Hand wash and let the band dry on the glass. Due to the variation in the circumference of the blown glass, your lid is hand fitted to the glass and may not be compatible with other lids.