The lamp tube specification

The lamp tube specification
D2S is used for the casting style lamps, for example, the pearl eye lamp. The light is casting on the ground through optics convex, because the convex has the up and down reversal specialty, adding the lens hood can cover in the upside light. So the pearl eye light is not glare. D2R is used for refraction style lamps, for example, the normal car head lamp. The light is reflecting to the ground directly, because the lens hood can not cover in the upside light totally, so the lamp is glare.