If your car is 2018 and earlier, the boots is an "Internal Fit" style; But if your car is a late model (like Camaro G6, Corvette C7, Subura STi 2018+ etc.), the boots could well be an External Fit style which IS NOT COMPATIBLE with those internal fit boots nor are for non Brembo calipers.
How to determine the boots dimension listed here?
If your pistons has 38mm in diameter (nominal), then DB-38 is for your "Internal Fit" style, but if you have "External Fit" boots you would add 3mm to the nominal diameter i.e. DB-41 (odd number) should be the boots to order. In general even number is for the internal fit and odd number is for the external fit.
Dust boots for the following calipers are known to have external fit boots however it's recommended to order through the car make to avoid mistake.