Blue K&N Filter - 3/3.5/4" Universal Kit

Ideal for open intake setups that are needing a replacement filter, does fit under mst heatshielding but touches lid on closing. 
 
Sounds great under throttle and when letting off! 
 
Each Kit includes the air filter and the rings to make it 3,3.5, or 4 inches diameter. 3.5 for gen 1 f series b58s, 4" for gen 2 g / supras