quality standards. Made of a blend of natural and butyl rubber. Tube Specifications:Valve stem type: TR-4 (straight metal stem (8 mm diameter)).Tire size: 90/100-14M, 3.00/3.50/4.10-14M. Fits: HONDA CR80 80-02, CR85 03-07, CRF125F 14-24, CRF150R IRC Heavy Duty tubes are designed and constructed to offer great performance in the most extreme motorcycle riding conditions. IRC heavy duty tubes are made 3 mm thick and puncture resistant, making them durable to better handle extreme and aggressive use. For maximum performance and durability, IRC tubes are made of a blend of both natural and butyl rubber. Heavy duty tubes are 3 mm thick and puncture resistant. Japanese tubes meet or exceed O.E.M.