The DEF Booty is designed to ensure that the cap and surrounding areas are clean prior to refilling the diesel exhaust fluid tank.

Impure DEF can clog the DEF injector and damage expensive components within the selective catalytic reduction systems. The DEF booty slips over the top of the DEF cap and attaches with elastic bands to secure it to the tank.

When it is time to refill a DEF tank, the DEF Booty can be pulled off easily and replaced with a new one when the refill is done. The DEF Booty is made of a durable polyethylene designed to resist tearing. The DEF Booty can also be used to help distinguish a DEF Tank from the fuel tank, preventing filling up the wrong tank with the wrong liquid.