What two pieces of information should be legible on a shackle?

The correct choice emphasizes the importance of safety and compliance in rigging practices. A shackle is a critical component used in lifting and rigging applications, and understanding the working load limit is crucial for ensuring that the shackle can safely handle the loads it will be subjected to. The working load limit indicates the maximum load that the shackle can handle without the risk of failure, providing vital information to users.

Additionally, manufacturing markings play a significant role in traceability and quality control. These markings can include the manufacturer's name or logo, as well as certifications that ensure the shackle meets relevant safety standards and regulations. Having these two pieces of information readily legible allows users to quickly verify the shackle's capacity and authenticity before utilizing it in any operation, thus enhancing safety and preventing accidents in the field.