No mil and mm are two completely different prefixes of units.
I agree 1mm is 1/1000 of a meter but 1mil is 1/1000 of an inch.
If panda film was 5.5mm thick it would be almost 1/4 inch thick which can’t be true.
I apologise. I thought you were using the shortened spoken version of millimetre - everyone says e.g. 20 mil instead of 20 millimetres where i live. Probably because that is the more commonly used unit in everyday life.
As you say, thinking about it film couldn’t be 5.5mm thick, rolls would be like linoleum!
Thank you for the gracious explanation.