Type of plastic in older Platypus Big Zip SL 2.0 L and 3.0 L?

[JustADude]

I've got an older (at least 1-1.5 yrs old) Platypus Big Zip SL 2.0 L and 3.0 L.

What type of plastic is in that Big Zip SL 2.0 L and 3.0 L?

That is, is it made from the following:
#2 HDPE (high density polyethylene), or a #4 LDPE (low density polyethylene), or a #5 PP (polypropylene)

Or is it #7?

Thanks for any details.