FTI / Finish Thompson EF, PF DEF Pumps - EFP / PFM Series available in various tube lengths. Diesel Exhaust Fluid (DEF) is for diesel engine vehicles which use Selective Catalytic Reduction (SCR) to control NOx emissions. Finish Thompson DEF Pump Systems easily, economically, and safely provide DEF transfer from a variety of containers into the vehicle’s on-board storage tank. FTI DEF Pumps are designed for years of reliable service while maintaining the strict purity requirements for DEF.