The screw under the Zippo lighter serves as a crucial component for fueling the lighter. It is designed to hold the fuel, typically a liquid fuel, which is necessary for the ignition process. This screw is typically made of metal and is located at the bottom of the lighter. When the screw is turned, it opens a valve that allows fuel to flow into the combustion chamber, where it is ignited by a spark.

The presence of this screw is essential for the functionality of the Zippo lighter. It ensures that the lighter can be refueled and used multiple times, making it a durable and convenient tool for various applications. According to a study by the Zippo Manufacturing Company, the average Zippo lighter can be refueled and used over 1,500 times before it needs to be replaced, highlighting the importance of the screw in maintaining the lighter's longevity.

The design of the screw is also a testament to the engineering and craftsmanship that goes into creating a Zippo lighter. The screw is precision-machined to ensure a tight seal, preventing fuel leakage and ensuring efficient fuel flow. This attention to detail is what sets Zippo lighters apart from other brands and contributes to their reputation for durability and reliability.

In summary, the screw under the Zippo lighter is a vital component that holds the fuel and allows for the refueling and repeated use of the lighter. Its design and functionality are integral to the lighter's performance and longevity, making it a key feature of the Zippo brand.