The millennium cover, also known as a "flip cap" or "spiral cap", is a common type of bottle cap widely used to seal various liquid containers. The name "Millennium Cover" comes from its design features, which allow the cap to be tightly screwed and opened or closed by flipping it over. Here are some basic characteristics of the millennium cover:

Sealing: The millennium cover is designed to provide good sealing to prevent liquid leakage and intrusion of external contaminants.
Spiral mechanism: The cap fits tightly with the bottle body through a spiral mechanism to ensure a sealed effect.
Easy to open and close: The millennium cover usually has an easy-to-operate flip mechanism, allowing users to open or close the cap with one hand.
Durability: High-quality millennium caps are durable and not easily damaged, suitable for long-term use.
Materials: Millennium covers can be made from a variety of materials, including plastic, metal, or glass, depending on the application and cost considerations.
Size diversity: Millennium covers come in various sizes to accommodate different bottle capacities.
Sanitation: Due to the ease of opening and closing, the millennium cover helps maintain the hygiene of the liquid inside the container.
Applicability: Millennium covers are suitable for various liquid containers, such as beverage bottles, food cans, and cosmetic bottles.
Cost-effectiveness: Millennium covers are typically low-cost and suitable for large-scale production and use.
Safety: Some millennium caps may have safety lock features to prevent children from accidentally opening them.
Design diversity: Millennium covers come in various designs, including different colors, patterns, and shapes, to meet different market needs and brand recognition.
Recyclability: Many millennium cap materials are recyclable, contributing to environmental protection.