Fasteners are various components used for connecting and securing objects. Here are some common categories of fasteners:

1. Screws: Screws are fasteners with threads, typically consisting of a head, threads, and a shank. Screws are often used in conjunction with nuts or threaded holes to secure objects together by rotating them.

2. Nuts: Nuts are components with internal threads, usually used in combination with screws. Nuts are used to secure objects by mating with the external threads of screws through rotation.

3. Bolts: Bolts are similar to screws, but typically have a specially designed head that does not require the use of a nut. Bolts are usually fastened by directly screwing them into pre-drilled materials.

4. Studs: Studs are fasteners with external threads, typically having threads on one end and a fixed head on the other. Studs are often used in conjunction with nuts to connect and secure objects.

5. Threaded Rods: Threaded rods are long, continuous metal rods with continuous threads on their surfaces. Threaded rods are commonly used for connections that require custom lengths or in applications that require larger gaps.

6. Helical Springs: Helical springs are springs with a spiral shape, commonly used to provide compression or tension forces to keep objects in resilient connection.

7. Locking Fasteners: Locking fasteners are a special type of fasteners, including nuts, screws, and bolts, with additional designs or coatings to provide stronger resistance against loosening and prevent fasteners from loosening under vibration or load.

8. Threaded Inserts: Threaded inserts are components used to enhance material strength and provide threaded connection points. They are typically installed in pre-drilled holes and provide an internal thread to receive screws or bolts.

9. Nails: Nails are straight fasteners commonly used for hammering or securing wood and other materials.

10. Rivets: Rivets are hollow fasteners typically consisting of a head and a hollow body. Rivets secure two or more materials together by forming a rivet head on one side and a flat rivet on the other side.