Which fastener typically requires a special tool for installation due to its design?

The snap ring is designed to fit into a groove on the shaft or inside a bore to hold components in place and prevent lateral movement. Its unique design requires a specific tool—often called snap ring pliers—for installation and removal. This tool grips the ends of the snap ring, allowing the user to compress it so that it can be placed or removed from its groove.

In contrast, rivets are typically installed using a hammer or a rivet gun, cotter pins can be inserted by hand, and clevis pins are also installed manually without special tools. The snap ring’s design and the functionality it serves in applications make its need for a specialized tool crucial for ensuring proper installation and retention.