Related Clues:

• Upper bound
• Put a ceiling on
• Bottle topper
• With 13-Down, they go off with a bang
• Mushroom top
• Excels
• Uppercase letters
• Yankees uniform item
• Bit of dental work
• Ball-player's headgear
• Small explosive
• Keep from increasing
• Headline features, briefly
• Souvenir shop purchase
• Twist-off thingy