Related Clues:

• Barrier for Superman's X-ray vision
• Assume command
• ''Get the ___ out!''
• What a salesperson may follow
• Spearhead
• Role for a star
• Soft metal
• Pioneer
• Be first
• *Rick Blaine in 17-Across, e.g.
• Play first
• Go ahead of
• Makeup of a heavy balloon?
• Plum role
• Balloon material?