This is a Rear Side window Mounted Fuel/Water Cell.  Left side Window Mount, Fuel Cell, and Window Cutting Guide. (all fuel cells are RED in color)

With the window cutting guide, Place the guide on the window in the recess and mark the window on the inside of the guide. The inside of the guide is just big enough to allow the Window mount to fit through. place the mount in the window and glue the tracing guide from the inside to help secure the mount into the window. 

 I am exclusively Authorized to sell prints on E-Bay for all designs sold by Spare-Time Hobbies. My authorization code is STH-EB101. Concerns should be direct to Adam at Spare-TimeHobbies "Email will be provided after the sale per ebay rules." Disclaimer: Due to the nature of 3D printing, items may contain visual blemishes. 3D printed product may require some trimming, drilling and painting for optimal visual appeal and proper fit; similar to what you would expect to do with modeling parts. 3D printed parts are formed at or above 200 degrees Celsius. Do not store in high temperature areas or in direct sunlight. Warranty: If your 3D Printed product becomes damaged within the first 30 days, one set of individual replacement parts are available upon request. Please e-mail a photo of the damaged part for review to determine if design or print was the cause of damage. After the first 30 days, replacement is at the discretion of the 3DPrinting Partner.