Abstract: Disclosed is a plastic lid for a container, which has a mounting hole in the lid's center and an in-and-out hole that is tightly closed until opened for the first time, and which has a plastic opening mechanism that can additionally pivotally cover the in-and-out hole. The opening mechanism has a valve that has a hole around which there are at least two latches which interact with a knob that has an arm terminated with a cylindrical element that has at least one carrier and is able to rotate in the mounting hole. The valve and the knob are sealed and immobilized with a plastic foil. Once opened, the in-and-out hole can be covered again using the valve and the mouth contact area using a plastic hygienic cover.