A pressure seal utilizes flexible materials such as foamed plastics (PE/PP/PS/EVA) or silicone sheet as liner. These are inserted into the bottle cap, and when the cap is twisted tightly, the liner is compressed between the cap and the bottle neck, creating an effective seal.

This sealing method is simple to operate and relatively low-cost, but it doesn’t have tamper-evident functionality.

It is often used together with one-piece or moon-tab induction liners. After user opening the seals, the foamed gasket allows for reseals many times, thereby extending the product in-use life.