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Halo ring sizes are listed by outside diameter in millimeters. An 80 mm halo has an 80 mm outside diameter; it is not a guarantee that the ring fits every projector headlight. Measure the actual mounting location and check depth before ordering.
Start with your headlight housing
Look for a vehicle-specific kit first. Match the year, model, trim and housing type, including whether the headlights are factory or aftermarket. If you are choosing universal halos, the measurement of the intended mounting area matters more than the vehicle name alone.
How to measure a halo ring
- Choose the mounting position. Decide where the ring will sit around the projector or reflector area.
- Measure across the outside of that area. Use millimeters and measure through the center of the intended circle.
- Check the opening inside the ring. Make sure the ring will not cover the projector or interfere with the required light path.
- Check depth and clearance. Allow room for the ring, mounting method, wiring and any diffuser before the front lens goes back on.
- Compare with the selected product. Confirm the available outside diameter and any other dimensions in the listing.
A measurement through the outer headlight lens can be distorted by its shape and viewing angle. Treat an external estimate as preliminary. Direct access to the mounting area provides a more dependable measurement, but opening a headlight requires the correct housing-specific process.
Common sizing questions
Will an 80 mm halo fit my projector?
Some projector surrounds use that size, but it is not universal. Projector size, trim shape, mounting position and housing depth can differ. Confirm measurements before choosing.
Should I round up or down?
Do not choose solely by rounding a measurement. A larger ring may hit the lens or trim, while a smaller ring may obstruct the opening or lack a mounting surface. Check the complete fit and ask for help if the available sizes fall between your measurements.
Does a diffuser change fitment?
A diffuser can change the ring’s overall dimensions and clearance requirements. Check the assembled dimensions if you plan to use one.
Choose your kit
Compare universal halo rings with vehicle-specific halo kits. If you need sizing help, send support the vehicle details, photos of your headlights and mounting-area measurements. Confirm current exchange terms before ordering rather than assuming an installed or modified ring can be exchanged.
Sizing examples
Use these images to understand the measurement approach; they do not establish fitment for every housing.
