# init(fuelMass:) Creates additional route information for fuel mass. ``` convenience init(fuelMass: Measurement) ``` ## Parameters `fuelMass` A measurement representing the fuel mass using @c NSUnitMass. Common units: - @c NSUnitMass.kilograms for compressed natural gas - @c NSUnitMass.pounds for CNG in regions using imperial units ## Return Value A new @c CPRouteDetail instance representing the fuel mass ## Discussion Use this method to display fuel levels for vehicles that measure fuel by mass, such as compressed natural gas (CNG) vehicles. \discussion CNG and similar compressed gas systems often measure fuel in mass units rather than volume due to the variable density under pressure. The system formats the mass measurement according to the user’s preferred units. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)