The product is a polypropylene which fits between the overlay of the bitchaman felt. The spring allows the felt to open which allows any warm moist air to evaculat ethe roof space and as this moisture is evacuated, fresh air is then allowed to enter the roof space, leaving any condensation

Brand Name	EASYVENT LTD
Colour	N/A
Material	Polypropylene
Manufacturer Model No	5000498760616
Wear Type	N/A
Type	Ventilation
Certifications Met	The British Board of Agrement
Country of Origin	UK
Protects From	Condensation
Waterproof	N/A
Number of Pockets	N/A
Pack quantity	5
Product width	65mm
Product depth	55mm
Product height	370mm