what kind of foil for 440c and 154cm

[Cardinal Knife]

Hey guys my search button has not been working since last night and I need to order foil today. I see grainger has 304,321, and 309 which grade do I need to order to wrap 440C and 154cm (the only two metals I have right now ready for treatment)
Thanks Chris

 

[Cardinal Knife]

...ordering 309