More and more airports are only selling water in aluminum twist top bottles – great for the environment but absolutely impossible to open with your hands without cutting them on the sharp ridges of the cap or destroying arthritic joints. These little guys are FABULOUS for just that task, and many other opening needs — those tight round inset caps on cardboard milk cartons, plastic bottle caps, etc. Small enough to tuck into a purse or pocket, lightweight for travel, they are absolutely the greatest!