The white bottle is for the Winter or Cold Weather and the Gray is for the Summer or Warm Weather. I am using the White bottle now along with a bottle of Lucas Oil Fuel Treatment, I add 16oz every other tank, I alternate them. I have no problems with anything so far and runs fine.

2007 Silverado 2500 HD LT Ext Cab SB/Black Ext/Ebony Int/ LMM Diesel