Michelin Heavy Duty Front Inner Tube Trial 2.75-21 2.75-21" Special Trial TR4 Valve Fits Front 2.75-21" Trials Tyres. Heavy Duty Reinforced Inner Tubes are 2.5mm thick. 

Michelin Heavy Duty Rear Inner Tube 80/100-12 2.50 / 80/100-12 TR4 Valve Fits Both Front Or Rear 12" Tyres  

Michelin Heavy Duty Rear Inner Tube 100/90-19 100/90-19" TR4 Valve Fits Rear 120/80-19" and 100/90-19" Tyres.  

Michelin Heavy Duty Rear Inner Tube 110/90-19 110/90-19" TR4 Valve Fits Rear 110/90-19" and 130/70-19" Tyres.  

Michelin Heavy Duty Rear Inner Tube 140/80-18 140-80-18" TR4 Valve Fits Rear 130/80-18", 140/80-18", 120/90-18" and 130/90-18" Tyres.  

Michelin Heavy Duty Rear Inner Tube 90/100-14 90/100-14" TR4 Valve Fits Rear 14" Tyres