Fiber optic headlight fiber optic headlight is focused the brightest white light available virtually shadow free. Fiber optic headlight is available with a variable 5-80mm light spot or with a fixed 80mm light spot at a 16” distance. At 16.5’ the spot size is 80mm for fixed or variable type headlight. • soft, flexible headband with a ratchet on the top and back for superior comfort and customized fitting. Fiber optic cable is 4.5mm dia. Of fibers & 230cm long with stroz type adoptor end.