600/700x21 Blockley inner tube. Super thick, butyl, correctly dimensioned unbelievable quality product from Blockley with rubber valve stem.

Nothing you can buy is as good as this tube that Blockley makes. This tube is also suitable for fitting in the 700x20 Blockley tyre. Remember that other tubes which are recommended for this range of tyre size, you will find are also recommended for 19" size tyres as well! Note that this is a dedicated tube size from Blockley for the larger 21" tyres, which can also be used on the larger 20" sizes. Unlike for example a Michelin inner tube which has a multi marked tube where the same tube recommended for a 600x19 tyre is also used in a 700x21 tyre - but at Blockley we produce additional tubes for the smaller section and diameter tyres! And our Blockley tubes are made from the best inner tube material, Butyl. Now you can hopefully appreciate why Blockley makes these correct dimension awesome quality reinforced inner tubes, which cost no more than the alternative . . . 

Because Butyl material is so good at keeping air in you will find butyl tubes available now often very thin, to save on material, which can lead to all sorts of unnecessary problems which a car owner should not be experiencing, so our Blockley tubes are as thick as tubes used to be, but also made from the best material available - this particular tube weighing 6lb, 12oz. That is why we make tubes, to compliment the awesome quality of our Blockley tyres.