Caps of plastic soda bottles aren’t the easiest to open. Typically, tight, they almost fuse with the bottle after it’s been opened once (and closed.) The build-up of pressure inside the bottle makes it hard to re-open it, without a wrestle.
The “soda valve,” designed by Korean designer Injoon Yang, is to the soda bottle what the corkscrew is to the wine bottle: an opener. All you do is securely place one of these ergonomic doohickeys on the regular cap, and turn the hand wheel. The cap should come off with little effort.