The Energi Inner Tubes are the product of years in the pursuit of quality. When buying Inner Tubes, of course, it’s important to get the right diameter, width and valve type for your bike. The size is written somewhere on the sidewall of the tyre and the valve is usually determined by the type of bike you have. Inner tubes typically state a wheel diameter and width range for which they will work, e.g. 26 x 1.95-2.125″, indicates that the tube is intended to fit a 26 inch tyre with a width of between 1.95 to 2.125 inches. On Road bikes you will see measurements like 700 x 18-23c, which means that the diameter is for Road, Cyclocross and Hybrid Bikes, and the numbers relate to the width are in millimetres, so 18mm-23mm wide.