This is a Coke (as in Coke-a-cola) Cozy. A way to insulate the cup to make the ice not melt and stop the condensation from running down the sides.
Normally the ice will melt within one hour, but with the Coke Cozy the ice lasts up to 6 hours. Better coke and not all watered down.
It stretched all out. Did 2 others that are better. Not the yarn or the lack of pattern, it is the knitter.