Tube Size: 280-250-4 (9-350-4, 8-300-4) Stem Angle Type: 90degrees/tr87 Manufactured By The World's Largest Tube Manufacturer under ISO 9001 certification Each tube is individually pre-aired and inspected utilizing advanced technology to ensure conformance to JIS (Japanese Industrial Standards) specifications Only The Highest Quality Butyl Rubber And Carbon black are used in the manufacturing process Advanced extrusion technology ensures consistency and eliminates thin walling problems common withother tubes