This size is suitable for classic letter-box style openings in fireplace surrounds. It will fit an opening thats 3 5 deep (75 125mm) by 10 15 wide (250 380mm). Reduces your energy bills by around 60 per year on average.
The Chimney Sheep 6 x 16 Inch Oblong Chimney Draught Excluder is perfect for chimney openings sized 3-5 inches to prevent draughts and obstructions.
