Related Clues:

• Ear part
• Fastening device
• Chest protector
• Lock part
• What a padlock may fasten
• Locking device
• A pin may go through it
• See 11-Down
• Martian feature
• See 51-Across
• See 16-Across
• Fastener
• Padlock's partner
• See 35-Down
• Part of a network, often