Which feature on a cuff key is used to activate the double lock?

• A. Key end/flag
• B. Double lock activator
• C. Teeth
• D. Swivel

Answer: (B)

The main idea here is understanding how a cuff key engages a safety feature that stops the cuff from tightening further. The component that does this is the double lock activator. It’s a distinct control built specifically to set the secondary locking mechanism, ensuring the cuff doesn’t close more once it’s in place. The other parts have different roles: the teeth interact with the lock's internal surfaces to operate the main mechanism, the key end or flag helps position or enter the lock, and the swivel lets the key rotate as you work it. So the double lock activator is the part you use to enable the double-locked state.