Which factor is least important when selecting a material for an "O" ring?

When selecting a material for an "O" ring, the most significant factors typically include compatibility with the fluids it will encounter, temperature resistance, and durability. Each of these factors plays a critical role in ensuring that the "O" ring functions properly and safely in its intended application.

Compatibility with fluids is crucial because the material must withstand chemical interactions without degrading or losing effectiveness. Temperature resistance is also vital, as "O" rings often operate in environments with varying temperature ranges, and failure to withstand these temperatures can lead to leaks or failures.

Durability ensures that the "O" ring can maintain its integrity over time, withstanding wear and tear from repeated use and exposure to environmental conditions.

While cost is certainly a factor when making any purchasing decision, it is typically regarded as the least important in this context. Selecting an "O" ring based solely on cost could lead to compromising on quality and performance, which can result in more significant issues and costs down the line if the chosen material fails to meet the demands of the application. Thus, cost should be a consideration, but it is not as critical as the other factors in ensuring a reliable and effective seal.