Primarily Petroliana Shop Talk Forums Shop Talk Petroliana Forums General Petroliana Discussion Fil-pruf bottle spout lettering

Hello everyone, can someone explain what the lettering was for on the filpruf spouts ?
Some had A - AF- H- HL and so on.
All information appreciated, thanks in advance.

the weight/grade of the oil .. ...

Would you happen to know which lettering applied to what weight?
Thanks .

mobil had charts recommending what too use & on what,
different grades in 2nd picture .. ...

Im looking to buysome that are H And HL i dont see them there coild you tell me what they mean please.
Are you willing to sell them or sell me some copies thank you in advance.

there is also reference too transmission/differential with different codes but I don't see any reference to the codes of
a H or HL in this '35 mobil chart .. ...

H stands for Heavy and HL is Heavy-Light
Used mostly in foreign markets I believe

Thank you all for your help very appriciated.

I know for certain that "H" was the aircraft grade because I own a gargoyle "H" grade one gallon can. I found it when I was 12yrs old at the Bennington, VT antique car show and I still have as of yet to meet anyone else that owns or even knows of one(that would make an interesting thread on its own). References to the gargoyle "h" grade were also made in several issues of the "gargoyle" vacuum oil new letter which I have packed away somewhere and feature beautiful pictures of early aircraft.