Twin Air air filter Yamaha/Fantic 450 23-

Twin Air air filters offer unsurpassed performance and protection. This is ensured by the high-quality materials and the superior two-part construction.
Open-pore foam on the outside to protect against dirt, soot and sand
The fine-pored inner foam acts like a second filter, retaining even the smallest particles while maximizing air permeability.
Outer and inner foam are firmly bonded together. This means that no dirt particles can get stuck between the two layers.
The extra-wide support foam ensures optimum contact with the air filter housing. At the same time, it acts as an air-permeable seal.