Thank´s Mr. Murrill.

Gracias al aporte del Sr. Murrill se ha agregado una identificación faltante en la Airborne, a continuación transcribo la explicación al respecto.

That TP would be "tire pressure" expressed in pounds per square inch.  I can't read the number in the picture, but it is probably very low for a fat tire like that.  The US Army always stencils the correct tire pressure near the wheel on all of their vehicles. My 53A has the same tires and wheels, so I will have to look that up.  Seems like it is about 12 pounds.  The 53 has no springs, so the pressure could be a bit lower to provide a softer ride. Those big tires are great on soft ground such as a beach above the high tide mark.