Related Clues:

• Exemplar of lightness
• Element like 8-Down
• Helium, e.g.
• Whistle blower?
• It can cause inflation
• Jingle
• Major cause of inflation
• It can be hot, thin or cold
• Main contents
• Road-sign word
• Get out in the open
• It may burn on the range
• Service station sign
• It's inhaled
• A lungful