What part of the article has it wrong? It says: >Unlike latex or rubber weather balloons which inflate and stretch as they rise into lower atmospheric pressure

What part of the article has it wrong? It says: >Unlike latex or rubber weather balloons which inflate and stretch as they rise into lower atmospheric pressures, these mylar balloons can't stretch, so their fully inflated ground size will be the same as their size at high altitudes, meaning the pico balloon won't get much bigger than 32". The parts that mention expansion say they're referring to latex balloons.