Review on Sun's Tea Double Walled Drinking Glass, Manhattan-Style Glass - Ideal for Hot and Cold Liquids, Whiskey, Bourbon, Vodka, and Scotch - Premium Borosilicate Clear Glass - Set of 2 by Aleksandre Crane

I don't know the production process of the jars, I think there will be some kind of bubble in the bottom center of the jar, nice round bubble in the center that I can deal with but one of my glasses has (see photo) there was a strange oblong bubble, now you can see it when i drink from a glass, it was just not acceptable for me, i bought it to have a good whiskey for myself and friends , to be honest the jar looks like something you can buy at a thrift store, I returned them. Another note I tried to contact the seller as there is a note in the box saying contact the seller first do not return to the store it has been three days and the seller does not respond.