Commercial Door Accessories Weatherstripping, Thresholds, Louvers, Gasketing, Smoke Seals and More! Since 1935, National Guard Products has been manufacturing the finest weatherstripping and threshold products, and now we have added a new lite kit and louver line for steel and wood doors. Today, we are your complete source for traditional door seals, door thresholds, gasketing, louvers, sound seals and door bottoms as well as the latest technology for positive pressure products including Edge Sealing Systems (Category G) ) for (Category B) wood doors to comply with International Building Code (IBC). We make it easy to find the products you need with over 20,000 products in our online database, we're sure you'll find the right match in minutes.