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.

Where else can I verify the 21L code?

Exterior & Appearance · 2023 Cadillac CT5 · 157 views · 2 replies Solved

21L — Secondary exterior color: Light Blue Metallic. This code identifies the factory-applied secondary paint used in a two-tone or special paint scheme. Browse RPO codes →

Mike T. Jul 5, 2026 · Georgia

I am trying to document the original configuration of a 2023 Cadillac CT5. Code 21L is shown as “Secondary exterior color: Light Blue Metallic. This code identifies the factory-applied secondary paint used in a two-tone or special paint scheme” Which source is usually most reliable when the build sheet, window sticker, and dealer printout do not use identical wording?

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2 replies

Tyler C. Jul 10, 2026 Accepted answer

A window sticker is helpful for customer-facing option names, while the build sheet is usually more detailed. If they disagree, the vehicle-specific dealer equipment list can help connect the sales name to 21L.

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Kyle P. Jul 12, 2026

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