PLEASE CALL BEFORE ORDERING. SIZES ARE VERY LIMITED A 9mm felt liner with the addition of a layer of radiant-text material makes this liner ideal for added warmth in our felt lined winter pacs. Comes in heights of 10", 12" or 14" heights. Will only fit in Hoffman Pacs that feature a 9mm felt liner. (Not made for thinsulate lined model boots.) A second liner is recommended with the purchase of all Hoffman winter pacs.