l 63 mm connection: 39mm foam with ally cap Product description Foam it! The POLINI foam air filters have perfect fi lter performance due to their enlarged intake surface; their air flow rate is very high. Better pull and light speed increase are your rewards. Attenzione: intake noise levels will be louder, raise jets! The filter is available in a variety of angles and lengths. Just the thing to suit your taste. OEM numbers (for comparisons): 203.0040 (POLINI)