The new standard 27.5 inch BBB BTI-68 27.5x2.1-2.35 FV-48 is made from a durable rubber compound. No seams that can leak air. Specifications: wheel size: 27.5"; allowable cross-sectional size of the tire: 2.1-2.35; wall thickness: 0.87 mm; category: universal. Nipple type: F / V-48 mm (French, presta). Manufacturer: BBB (Holland).