The ProVision Fiberoptic Scope from SLI Lighting is used like a telescope for looking inside otherwise inaccessible work areas. This tool is great for looking inside drainpipes, engines, vents and behind walls. It requires an opening of only a 1/2 inch in diameter, allowing the user to inspect for problems such as frayed or loose wiring, lost objects or obstructions. It features a flexible 18 inch cable for positioning its optical lens. A built-in battery-operated light source illuminates dark areas.