DT-1ﾑs world-class foam technology delivers maximum airflow whilemaintaining critical engine protection, Their Super Seal base eliminates the need for grease and creates thecleanest 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