The short answer

The best windshield shade is the one that covers the glass without becoming a lever against the camera housing, mirror, dashboard, or seal. Modern windshields may contain driver-assistance cameras, rain sensors, heads-up-display areas, or antennas, so a generic rectangle can fit the glass and still be a poor fit for the vehicle.

Measure the upper edge

Area Record Why it matters
Glass width At top, middle, and bottom Windshields taper and curve.
Camera housing Width and projection from glass The shade may need a notch or specific fold.
Mirror mount Location and clearance Pressure can move or stress the mount.
Dashboard Contact line and sensor openings A hard edge can scratch or block sensors.
Visors Whether they hold the shade without force The visor should not be overloaded.

Install and remove the shade while parked, without dragging it across the camera or mirror. Fold it as instructed so the reflective surface does not scratch the interior. If a warning appears after an accessory has pressed or shifted a camera housing, remove the accessory and obtain qualified advice.

Limits

This is a fitment guide, not a sensor calibration or heat-performance test. Follow the vehicle and shade instructions.