If I had only known about this when I was wiring my phone system! It is a pricey toy, but well worth it if you are going to be fishing wires and doing electrical work, especially in an old home. It comes in varying lengths, but the ProVision100 has a flexible 18 inch fiber optic arm. It features a 40 degree wide field of view, up close focusing, and a 2.5 volt lamp to shed light on the situation. In my case it probably would have saved about 20 holes I cut into our walls in bad places.
Made by Provision, and available for about $250 at Amazon.com and other tool dealers.
About Marc Lyman