A super thick extra heavy duty Blockley tube marked 600/650x19 only. The tube you would use when using a larger 19" tyre or on the Peking-Paris where you want something  exceptional. This was why we were asked to make them. A superb quality rubber valve stemmed super thick reinforced butyl inner tube. A great product.

These inner tubes can fit in our Blockley 600x19 tyres (marked "550/600x19"), but are really ideal for for the larger 19" tyre sizes such as 650 and 700x19.

This is an even thicker heavy duty tube than our already plenty thick standard tube. This heavy tube is ideal for very arduous conditions.