Which type of rivet features a hollow design?

The choice that features a hollow design is Rivnuts. Rivnuts, also known as blind rivet nuts, are designed with a cylindrical body that has a hollow center. When installed, the body is deformed or expanded to securely grip the material, allowing for a strong, threaded anchor point in sheet metal or other materials where a through-hole cannot be accessed. This design facilitates easy installation from one side, making them ideal for applications where access to both sides of the material is limited.

In contrast, solid rivets are solid throughout and have a different installation method that typically requires access to both sides of the material. Hi-Shear rivets are a type of solid rivets designed to withstand shear loads but do not feature a hollow design. Blind rivets do have a hollow body, but they are different from Rivnuts in that they provide a permanent, non-threaded fastening solution. Therefore, Rivnuts are the correct choice when discussing rivets with a hollow design that provide a specific functionality in fastening.