This 60/100-14(2.50-14) inner tube (innertube) is commonly (though not exclusively) associated with 50cc, 70cc, 90cc, 110cc, 125cc, 140cc, 150cc , 155cc and 160cc dirt bikes / pit bikes. Most commonly used as the front wheel tube in 12 inch rear / 14 inch front configurations.
 
Commonly associated denotations:
60/100-14
2.25-14
2.25/2.5-14
2.5-14