Sturdy and wearable; Extremely sharp; Fine ductile; Long service life High quality; Inner Diameter (intake side): Approx 17.5mm; Outer Diameter (intake side): Approx 23mm; Diameter (air filter side): Approx 37.4mm For models: for Aprilia Mojito Custom 50 (Piaggio engine); for Aprilia Sportcity ONE 50 (2-stroke); for Aprilia Sportcity Street 50 (2-stroke); for Aprilia SR 50 Funmaster LC (from 03/2003) (Piaggio engine); for Aprilia SR 50 Street LC (water) (Piaggio engine); for Aprilia SR 50 R LC (water) (from 2005) (Piaggio engine); for Aprilia SR 50 Racing LC (water) (from 07/2003) (Piaggio engine); for Aprilia SR 50 Sport LC (water) (from 07/2003) (Piaggio-Motor-DiTech) for Derbi Atlantis 50 AC (air) (from 06/2002) (Piaggio engine); for Derbi Atlantis 50 LC (water) (from 06/2002) (Piaggio engine); for Derbi Boulevard 50; for Derbi Bullet 50; for Derbi GP1 50; for Derbi GP1 50; for Derbi GP1 50 Revolution; for Gilera DNA 50; for Gilera Easy Moving 50; for Gilera Ice 50; for Gilera Runner 50 DT (until 1999); for Gilera Runner 50 (YOC 1999-2000); for Gilera Runner 50 (Bj. 2004-08/2005); for Gilera Runner 50 (YOC 2001-2004) for Gilera Runner 50 SP (from 08/2005) (C46100); for Gilera Stalker 50 (from 1999); for Gilera Stalker 50 (until 1999); for Gilera Stalker Naked 50; for Gilera Storm 50 (from 2007); for Gilera Storm 50 (until 1999); for Gilera Typhoon 50; for Gilera Typhoon-X 50; for Italjet Jet-Set 50 (2-stroke); for Italjet Torpedo 50 (Piaggio engine); for Piaggio Diesis 50; for Piaggio Fly 50 (2-stroke) for Piaggio Free 50 (from year 1999); for Piaggio Free 50 (until 1999); for Piaggio Liberty 50 (2-stroke); for Piaggio NRG 50 LC (water) (SAL1T); for Piaggio NRG 50 MC2 LC (water) (C04); for Piaggio NRG 50 LC (water) (SAL1T); for Piaggio NRG 50 MC2 LC (water) (C04); for Piaggio NRG 50 Extreme AC (air) (C21); for Piaggio NRG 50 Extreme LC (water) (