Plastic caps are currently commonly used packaging forms for bottles, cans, and barrels, and are especially widely used in beverage, chemical, and pharmaceutical fields. According to their uses, they can be divided into breathable plastic caps and air-impermeable plastic caps. 1. There is a ring-shaped leak-proof ring on the inner wall of the top of the general plastic cover; there are also ordinary plastic bucket covers that need to match the inner cover, so there is no need to design a leak-proof ring; 2, the lower end of the plastic cover is connected to an anti-theft ring through a tension stiffener; 3. At the same time, there are several flaky whirling pull wings evenly distributed on the inner wall of the anti-theft ring; the plastic bucket lid designed in this way has a firm sealing, leak-proof and anti-theft performance, safe and convenient to use, and can effectively prevent the liquid in the container from being By external pollution, it can ensure that the packaging of various liquid products meets the characteristics of safety standards.