Host Wine Freeze Cup Set of 2 - Plastic Double Wall Insulated Wine Cooling Freezable Drink Vacuum Cup with Freezing Gel, Wine Glasses for Red and White Wine, 8.5 oz Grey - Gift Essentials

It took a year of trial and error to perfect the exact "ultrasonic welding" geometry that joins the clear plastic parts together and allows this cup to mimic the elegant shape of an actual stemless wine glass. The plastic had to be engineered to handle expansion and contraction from the gel freezing as well as extreme cold and warm conditions.