Related Clues:

• Rubber ring
• Flood insurance?
• Weatherproofer, e.g.
• It may be under a coat
• This might be blown, figuratively
• Type of seal
• Leak preventer
• Blow it and you see red
• O-ring, e.g.
• Leak stopper
• Pipe application
• Engineering ring
• Water-proofing stuff
• Sealing ring
• Caulk, say