1. A piece of coated transparent material intended to go in a lighting fixture to extend the life of any color media. Heat Shields are placed in the beam of the fixture, they reflect infra-red energy, therefore reducing infra-red heat, while still outputting around 80% of the light. Different versions are available from each of the "big four" color companies: Rosco, Lee, GAM, and Apollo. 2. May also refer to a Zetex border, hung on an electric batten to prevent hot lights from contacting adjacent scenery or drapes.