This cap is to aid in changing the fuel filter for a Cummins engine part number FF63054NN (filter not included in sale) with this cap it aids you so you don't spill when having to maneuver the filter out of the vehicle that sometimes makes you turn it sideways just to get it out. 
 
Note to user. cap has two tangs with one being placed higher than the other. if it starts to go on sideways spin the cap 180 degrees and try again and it should go on flat. 
 
 
CLIMATE NOTE: This is printed in PLA plastic which is known to warp in higher temperatures or become brittle when exposed to UV light. If your car is in a hot climate and in the sun, the high temperatures (>125℉) and direct sunlight could warp this adapter or cause it to break. This particularly applies to places like Phoenix, Southern California, etc. where temperatures regularly reach into the 100℉. An average "hot" summer day in Minnesota, or Wisconsin, or New York could also warp these if your car sits in the sun! 
 
This product is 3D printed. Due to the nature of 3D printing, there may be a seam, layer lines, and/or small imperfections.
 
Washing instructions: Hand wash only with cool, soapy water. Rinse and dry.