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6" Insul-Plug - 810106

Item: COP34200
  • Constructed of a ceramic-based fireproof insulating material
  • Black outside plate covers up to a 10" diameter hole
  • Simply insert it into the old thimble opening and tighten the expansion screw on the face
  • The sides expand and create a tight fit inside the thimble opening
  • It can be removed by reversing the process

6" Insul-Plug - 810106

This Insul-Plug blocks old, unused thimble holes in masonry chimneys. It provides a thermal break from combustibles and prevents downdrafts from entering the room.

WARNING: Carcinogens: This product can expose you to chemicals including Lead, which is [are] known to the State of California to cause cancer. For more information go to

10-Year Warranty