This looks like good stuff and not too bad a price. Also take a look at the Bendaway Plus and Bendaway S in stainless at the bottom. Also not badly priced for 25 feet.
(broken link removed to http://www.ducting.com/Bendaway_A.html)
(broken link removed to http://www.ducting.com/Bendaway_A.html)
....plenty for an OAK. You don't need anything like stainless.

![[Hearth.com] OAK Flexible Metal Pipe [Hearth.com] OAK Flexible Metal Pipe](https://www.hearth.com/talk/data/attachments/92/92040-370d2cc4bfe2093ac6394df12e1a9f2a.jpg?hash=kXFKJvQJn5)
![[Hearth.com] OAK Flexible Metal Pipe [Hearth.com] OAK Flexible Metal Pipe](https://www.hearth.com/talk/data/attachments/92/92041-7fd0823a9cc2cdeb15ab249b91e6c0aa.jpg?hash=m5BIoXBKrA)
![[Hearth.com] OAK Flexible Metal Pipe [Hearth.com] OAK Flexible Metal Pipe](https://www.hearth.com/talk/data/attachments/92/92042-ae87e3796a96693b0854f0230a3fe5c2.jpg?hash=ZTZ6DPnwiH)
![[Hearth.com] OAK Flexible Metal Pipe [Hearth.com] OAK Flexible Metal Pipe](https://www.hearth.com/talk/data/attachments/92/92043-d10e7f8fd9c95b9775ea9f1ff9d4be40.jpg?hash=7_-8QtosV0)
![[Hearth.com] OAK Flexible Metal Pipe [Hearth.com] OAK Flexible Metal Pipe](https://www.hearth.com/talk/data/attachments/92/92044-be0cb2ed0ec04486b95c0c461a6b907e.jpg?hash=vaADcWlw3A)