All Metzeler tubes are made from natural rubber blend and feature heavy-duty construction for excellent service and puncture resistanceFor Valve Stem Types, see page ??? FOR RIM SIZE18?INNER TUBE VALVE STEM TYPE EU34G| TR-4| V1-09-1INNER TUBE VALVE STEM TYPE USTR-4 (round base) Center Metal Valve (threaded and nuts)MATERIALRubberPRODUCT NAMEInner TubeTUBE FITS TIRE SIZE100/90-18| 110/70-18| 110/80-18| 110/90-18| 120/70-18| 130/60-18| 130/70-18| 3.25-18| 3.50-18| 4.10-18| 4.25/80-18| 4.60-18TYPEMotorcycleUNITSEach