This is the inner tube size most commonly used on push chairs - 12 inch, with a Schrader / car type valve. This tube has a valve with a 45 degree angle to make attaching a pump easier on a small wheel.
Weight: 115g
Schwalbe tubes cost more - but you pay for the enhanced quality, they test all tubes (twice), including inflation for 24 hours to ensure they don't lose air pressure.
Less lost air means less time inflating.
Manufacturers code (Schwalbe): AV1 45 degree
This inner tube fits ETRTO tyre sizes as shown below:
47-203 - 12 1/2 x 1.75 inches
50-203 - 12 x 2.00 inches
54-203 - 12 x 2.10 inches
62-203 - 12 1/2 x 2 1/4 inches
Valve type: Schrader / Auto / Moto / American 8mm diameter, with 45 degree bend
Valve length: 40mm
Previous barcode: 4026495876041