Which factor is least likely to affect the selection of a rivet gun?

The selection of a rivet gun is primarily influenced by factors that significantly impact the performance and suitability of the tool for a specific application. The type of rivet used is crucial as different rivets require different amounts of force and precision, which directly correlates with the capabilities of the rivet gun. Material thickness is also a key consideration, as thicker materials may require more powerful rivet guns to properly install rivets without causing material damage. Environmental conditions can affect both the tool and the materials being worked with, influencing factors such as temperature and humidity, which can alter the performance of the rivet gun.

In contrast, the color of the rivet does not have any functional implications regarding the performance of the rivet gun. While color may be relevant for aesthetic purposes or identification, it has no bearing on the mechanical aspects of rivet installation. Therefore, it is the least likely factor to impact the selection of a rivet gun.