A Impac bicycle tube is predominantly made of Butyl rubber.
Butyl is a very elastic and airtight synthetic rubber.
This high elasticity Impac tubes allows a wide range of different tire sizes to be covered.
Specifications:
Brand: Impac
Wheel size (inch): 27.5 / 28 / 29
Valve type: Schrader and Presta valve (Sclaverand)
Valve length: 40 mm
Valve diameter: 5,9 mm
Maximum valve pressure 15 bar (Keep the maximum tire pressure in mind)