50mm SSP-G Non-EGR Cylinder Head for 50cc 4-Stroke 139QMB ScootersSPECIFICATIONS: Intake Valve Diameter: 23mmIntake Port Diameter: 21mmExhaust Valve Diameter: 20mmExhaust Port Diameter: 18.5mmValve Length: 62.3mm (compatible with 64mm Short Valve Style Heads) COMPATIBILITY: Amigo – 50cc 4-Stroke ScootersApollo – 50cc 4-Stroke ScootersBaotian – 50cc 4-Stroke ScootersBaron – 50cc 4-Stroke ScootersBintelli – 50cc 4-Stroke ScootersBMS – 50cc 4-Stroke ScootersCoolster – 50cc 4-Stroke ScootersCSC – 50cc 4-Stroke ScootersDiamo – 50cc 4-Stroke ScootersFlyscooter – 50cc 4-Stroke ScootersIce Bear – 50cc 4-Stroke ScootersItalica – 50cc 4-Stroke ScootersJCL – 50cc 4-Stroke ScootersJonway – 50cc 4-Stroke ScootersKandi – 50cc 4-Stroke ScootersKinroad – 50cc 4-Stroke ScootersKMD – 50cc 4-Stroke ScootersKymco – 50cc 4-Stroke ScootersLance – 50cc 4-Stroke ScootersLeike – 50cc 4-Stroke ScootersLinhai – 50cc 4-Stroke ScootersLongbo – 50cc 4-Stroke ScootersMotobravo – 50cc 4-Stroke ScootersMotofino – 50cc