DT-1ﾑs world-class foam technology delivers maximum airflow while maintaining critical engine protection, Their Super Seal base eliminates the need for grease and creates the cleanest and best seal on the market, All DT-1 Air Filters are handmade in Belgium with the highest-quality bonded dual, triple and evolution foam available, DT-1 Air Filters come standard or pre-oiled with highest-quality flame-resistant bio-degrable filter oil, SUPER SEAL STANDARD DUAL LAYER FOAM AIR FILTERS, DT-1 standard air filters are constructed with high-quality 15 mm dual-stage foam, Custom-designed for each air box and filter cage for the best fitment and performance