What does a used car light bar ball mean?

Plastic bumper and ball head under used car headlights.

Light bar ball refers to the problem that the lampshade of a vehicle is damaged or broken, which affects the lighting effect and driving safety of the vehicle. Damage or rupture of vehicle lampshade will lead to light scattering, light leakage or abnormal focusing, which will reduce the lighting effect. Affect the driver's visibility to the road and surrounding environment, and increase the risk of accidents.