The Cyprus glass cup is hand-blown by expert glassblowers. It is actually two cups that are each made by hand and then put together to make it into a double-walled glass cup. Because it's hand made every cup is unique. So you may find small bubbles in the glass. These small bubbles are not defects but an indication of the handmade glass blowing process.
The glass that it is made of is called borosilicate glass. This type of glass is a high-grade thermal glass. It’s heatproof, can easily withstand boiling water, and will never go cloudy even after years of use.
This glass cup is also top-rack dishwasher safe.