What is a window sticker?

A window sticker — officially the "Monroney label" — is the printed sheet the factory attaches to the window of every new vehicle. It has been federally required on new cars in the United States since the Monroney Act of 1958, and decades later it remains the single most authoritative summary of how a particular vehicle left the assembly line.

It lays out the standard equipment, the optional equipment and packages the original buyer selected, the EPA fuel-economy ratings, the warranty terms, the percentage of U.S./Canadian parts content, and the full price breakdown — base MSRP, each individual option, the destination charge, and the grand total. That original data is exactly what lets you confirm, years later, how a used vehicle was really configured.

Window sticker vs. build sheet

The two documents describe the same factory configuration in different ways. A window sticker is written for the buyer: plain equipment descriptions, fuel-economy ratings, warranty details, and a price breakdown right down to the destination charge.

A build sheet is the factory's own assembly record — the complete list of option codes a vehicle was built with, without pricing. WindowStickerVin.com returns the window sticker whenever one is on file, and automatically falls back to the build sheet when it isn't, so you always come away with the underlying factory data either way. For a deeper comparison, see our guide on window sticker vs. build sheet.

Why check your window sticker or build sheet?

Whether you're buying a used car, selling one, arranging insurance, or just settling a curiosity, the factory record is the most reliable way to confirm exactly how a vehicle was equipped the day it was built — far more dependable than a listing description or a faded memory.

It lets you verify the trim level, the engine and drivetrain, the option packages, and individual features, and it makes it easy to tell factory-installed equipment apart from anything a dealer or previous owner added afterward. For buyers especially, it's a quick way to make sure a seller's claims actually match how the vehicle left the line.

RPO Codes Explained — Reading Factory Option Codes by VIN

Every GM vehicle is built to a list of RPO codes. Understanding them is the key to reading a build sheet and confirming exactly how a vehicle left the factory.

What is an RPO code?

An RPO code — Regular Production Option — is General Motors' standard way of recording a vehicle's configuration. Each code is a three-character combination of letters and numbers (for example Z71) that stands for one specific option, package, or piece of equipment.

A vehicle's complete build is simply the full list of RPO codes it was assembled with — engine, transmission, axle, suspension, paint, interior, wheels, audio, and every package in between. That list is what the build sheet shows.

Where are RPO codes located?

The Service Parts Identification (SPID) label — a sticker inside the glovebox, console lid, or spare-tire well listing the RPO codes.
The factory build sheet — the complete, definitive list, retrieved by VIN. That's what this site pulls for you.
The window sticker (Monroney label) — translates the key options into plain descriptions for newer vehicles.

Common GM RPO code examples

Code	Equipment
Z71	Off-Road Suspension Package
G80	Locking / limited-slip rear differential
NHT	Max Trailering Package
Z85	Standard / heavy-duty suspension
LS3	6.2L V8 engine
L86	6.2L V8 EcoTec3 engine
L83	5.3L V8 EcoTec3 engine
LFX	3.6L V6 engine
UQA	Bose premium audio system
AG1	Power driver-seat adjuster

These examples are for illustration. The exact meaning of a code can vary by model, year, and GM division. Your VIN's build sheet is the definitive source.

What about Chrysler, Jeep, Dodge, RAM, Fiat & Alfa Romeo?

FCA / Stellantis vehicles don't use "RPO" codes — instead they use factory sales codes. The idea is identical: a coded list of the options and equipment the vehicle was built with, printed on the factory build sheet. See equipment examples, or enter any supported VIN on the home page to pull the build sheet.