Builder's Best UL 181 Flexible Foil Ventilation Duct, 4" x 8', Aluminum/polyester

This wire helix product features steel wire support with a multi-ply design of metalized polyester and aluminum/polyester laminate. It is UL® 181 listed and labeled as a Class 1 Air Connector.

UL® 181, Class 1 air connector label
Multi-ply design of metalized polyester and aluminum/polyester laminate
Steel wire support
3″ dia. has ¾” pitch
4–12″ dia. has 1″ pitch­
UL® sticker every 10 feet
Maximum velocity rating 5000 fpm