Designed to fit in the factory airbox UNI FILTERs high air flow, superior dirt stopping ability, and long lasting dependability have made the PRO COMP II. The best selling replacement air filter for competition motorcycles. The UNI FILTERs unique two-stage design allows for easy and complete cleaning. The outer layer can be used dry as pre-filter allowing for longer intervals between cleanings, or it can be oiled for superior engine protection in unusually wet conditions. The inner filter must always be oiled.