<P> Coffee cup sleeves, also known as coffee sleeves, coffee clutches, coffee cozies, hot cup jackets, paper zarfs, coffee collars, coffee sleeve, and cup holders, are roughly cylindrical sleeves that fit tightly over handle-less paper coffee cups to insulate the drinker's hands from hot coffee . Coffee sleeves are typically made of textured paperboard, but can be found made of other materials . Coffee sleeves allow coffee houses, fast food restaurants, and other vendors to avoid double - cupping, the practice of using two (or more) nested paper cups for a single hot beverage . Some paper cup holders carry advertisements . </P> <P> The coffee sleeve was invented in 1991 by Jay Sorensen and patented in 1995 (under the trademarked name Java Jacket), and are now commonly utilized by coffee houses and other vendors that sell hot beverages dispensed in disposable paper cups . There are a number of patents that cover various coffee sleeves and their aspects . Other people have claimed to invent the coffee sleeve . </P>

What is the cardboard sleeve on a coffee cup