Do these mount to the window glass or the body?

They mount to factory points on the quarter panel structure, not the glass itself. Test-fit before final fastening to confirm attachment method.

Will I need fasteners or adhesive to install these?

Mounting hardware is not included. Check your fitment and vehicle condition before committing to bolts or adhesive — some installations work better with one method over the other.

Can I return these if they don't fit right?

These are made to OEM specs for your vehicle, so check the fitment carefully before installation. Once mounted, returns depend on condition — contact ModSupply directly with photos if there's an issue.