What is a fin seal?

Thanks for writing in! A fin seal is a pliable vinyl strip that runs along the full length of the pile weatherstrip. It's an additional precaution to prevent moisture from dripping into the house. 

It works very well at doing its job, but it's important to note that it's not applicable to all windows. If you try using a rainstrip pile to repair a window that didn't use this type originally, then the window might become harder to operate due to the friction provided by the extra material. When in doubt, replace like with like. Always stick with the same size and style wool pile you had originally.

I hope this answered your question, but please get back to us if you need anything else.