Summary: the heat to pass through A heat filter reduces the heat that passes into the light guides still further so that very little heat reaches the subject even though the light is very bright Fostec Ace light source with a Y shaped light guide supported by a Manfrotto 035 Super Clamp on a Manfrotto 345 Table Top Kit The most common bulbs have the ANSI codes DDL EKE and EJA
Image Dimensions: 535 x 448
Image originally found here.