Universal B-Vent cap is self-centering and has an adjustable design for a neat, quick and easy installation. Created for roof vent, flue and B-vent installations, this new design supports venting a strong draft. Constructed from aluminum for rust and corrosion resistance, the cap will also prevent rain, debris and most pests from entering the vent. Not to be used on solid fuel flues. Listing: UL 441 and CAN/ULC-605.