This is the most innovative T&G design in the industry. Not only does it really seal the wall from air or water getting in but it makes for a very air-tight condition for energy efficiency. This T&G design will be available in all of our profiles. The following is an illustration of it on a round log. This log could have been a swedish cope profile...but if you want the most advanced in T&G design...here it is.....this is a Sierra exclusive!