Dolan-Jenner (?) Fiber Optic Light Guide Cable for Illuminator I hooked it up to a light source and it works great. I only have the accuracy of a measuring tape but the diameter of both ends looks to me to be about 5/16" in diameter. The length from end to end looks to me to be about 23" not including the curve part on the end. At the time of this listing we have more than one of these and so you may not receive the exact one shown but they are all in the same condition and have been tested with a light source. The last pictures shows all of them at the time of listing and so you will receive one of the cables shown in the last picture. wf R7-7 fdk 80602198