Change in focal length and concentrating width of the Halogen Line Heater HLH-65/f75 HEAT-TECH info 8 years ago This video is a demonstration to confirm the concentrating width of the Halogen Line Heater HLH-65/f75. Related page: Change in focal length and concentrating width of the Halogen Line Heater HLH-30/f20 Change in focal length and concentrating width of the Halogen Line Heater HLH-55/f25 2-4.Focal Length and Focal Diameter of Halogen Point Heater 3-4.Focal length and focal width of Halogen Line Heater Focal length and focus diameter of the Halogen Pont Heater HPH-18 Focal length and focus diameter of the Halogen Pont Heater HPH-35 Focal length and focus diameter of the Halogen Pont Heater HPH-60/f60 Focal length and focus diameter of the Halogen Pont Heater HPH-120/f45