Jar and Bottle Opener The Jar Opener can aid individuals with a weak grip or decreased sensation in their hands to open stubborn jars or pots. It is, however, not limited to the kitchen; It can also be used to open doors or turn on taps around the home. The Jar and Bottle Opener has been specially designed to fit various sizes of bottles and caps from 1 to 3 inches. It also allows a tight grip on small cupboard doors. Its domed shaped fits comfortably into the palm of the hand.