Polaris RZR 900 Trail Complete Door Insert Kits. Door Inserts for the Polaris RZR 900 Trail, constructed from a powder-coated mild steel tube frame and plastic skins. We use a top quality thermoplastic high-impact polypropylene which offers a high-gloss finish with excellent durability and is available in several colors. These inserts help keep debris out of the cab while you are operating your UTV. A nice alternative to the much more expensive OEM inserts. These inserts install easily using existing mounting locations. All hardware included for installation. While not designed to be water tight, these inserts do help a great deal in protection from from the elements and greatly enhance the RZR s looks.