The Ruebena 12.5 Inch Bike Inner Tube Set is perfect for kids' balance bikes or prams, with a diamter of 12.5 inches and a Schrader/Car valve type. Made of durable rubber in the Czech Republic, they have a standard valve length of 35mm and are designed to fit inside all tyres of between 1.75" and 2.45" wide, making them perfect for the vast majority of 12.5 inch tyres. 
If you are unsure if these inner tubes will fit your needs, please send a photo of your bike and we can advise you.