Good for use in both summer and winter months to stop unfriendly drafts and wind noise Perfect for using on interior or exterior doors and windows. It is very Safe, Economical and Practical. Twin Draft Guards are double sided to provide double Air-Leak protection and move with the door when opening and closing Stop drafts from doors and windows for good with the Twin Draft Guard. The draft guard has been designed to snuggly hug doors and windows so that you're protected from drafts from both sides. Once you've cut the special insert to size, just slide it into place and you're done! No need to keep adjusting or fussing with it like other door draft stoppers. You can save a lot of power if you are running an air conditioner in your room. An AC needs to work harder if there is air leakage from the room, especially from under the door. Stop those air leaks and save money on electricity bill.