Pro-Guard D2 Fuel Filters deliver increased flow and efficiency that are demanded in a Diesel environment. These filters use an exclusive NF21 synthetic media for maximum filtration and minimal flow restriction. aFe Pro-Guard D2 fuel filters have up to a 99 filter efficiency for maximum protection. GM Diesel Trucks 01-16 V8-6.6L (td) LLY/LBZ/LMM/LML