Michelin Airstop A2 Butyl Inner Presta Valve Road Tube - 700c X 25-32mm From  £4.49

I was impressed with the efficiency of Total Cycling. I have had Michelin Airstop tubes before and they have always been reliable. However the ones I have had before have always had a locking nut on the valve so that it can be tightened on the rim. There is no thread on the valve now so that they cannot be tightened down. This makes inflating the tyre difficult.